An understanding of fish evolution (and other stuff)

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elephantnose3334

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I have lots of questions.

I'm one of those few teens that like fish a lot. Following my dad's (he was a young boy when he kept fish and gave up on them) footsteps of being a fishkeeper. I understand that there are hard things regarding the hobby, but learning about fish evolution is harder for me. I never heard about the evolution of certain aquarium fish before. Freshwater fish evolution would be a new topic for me on the aquarium hobby. For example, rainbowfish. Some said they evolved over 10,000 years from marine ancestors. It's weird that evolution of freshwater fish usually comes from the marine ancestors but I'm still learning as I go through years of the hobby. Regarding the rainbowfish, what did the marine ancestors look like before they died out and evolved to the rainbows we know today? Are there scientific breakthrus on aquarium freshwater fish evolution for a while? The other things I might ask is how do some aquarium fish have unique adaptations to go through life? Or maybe how did the fish evolve to become schooling fish? How did South American tetras evolve on what they are today?

I am interested in fish because they're interesting animals and they're mostly easier to care for than most pet mammals i.e. cats and dogs. I have an understanding on how to look after them and currently keep two species of tetra in a 40L tank. My mistake, but I was a beginner and I should know better. How do fish communicate to each other? I don't hear most species communicating each other in my POV.

And finally, native fish I haven't heard of before. I heard of the salamanderfish before, but not the nightfish, a WA native. Have the nightfish been bred in captivity? What are some other natives I haven't heard about? I fear that the local government might do the wrong thing on the native fish again.

Thank you.
 
Wow, you're asking a lot of good questions! I'll try to answer some of them. I'll make the disclaimer that fish are not my specialty, but I do know a good deal about evolution in general.

It's weird that evolution of freshwater fish usually comes from the marine ancestors but I'm still learning as I go through years of the hobby. Regarding the rainbowfish, what did the marine ancestors look like before they died out and evolved to the rainbows we know today?
Well, the thing about fish is that they all had to start somewhere, and that was the ocean! All life began in the ocean and so that's also where fish first evolved. Now, of course, once fish made their way into freshwater, they continued evolving, so there are plenty of freshwater fish that evolved from other freshwater fish. However, many saltwater species that may be more recent in evolutionary history continue to evolve into inhabiting freshwater. This happens more commonly with saltwater species that live on the coast in estuarine habitats that have influxes of freshwater. There are some rainbowfish species that have native ranges in coastal regions. These would be the species that stuck around in brackish water.

As for what the rainbowfish ancestor looked like, I'm not sure if that's even known. When it comes to studying evolution, we often discuss something that's called a "most recent common ancestor", which is a theoretical singular organism that is the ancestor of an entire group of organisms that evolved from it. The vast majority of the time, we have very little idea about what these common ancestors look like. Sometimes we can guess what they looked like, but we almost never have fossils of them. I don't know if anyone out there has made a guess about what the most recent common rainbowfish ancestor looked like, but I wouldn't be surprised if no one knows for sure.

The other things I might ask is how do some aquarium fish have unique adaptations to go through life?
The secret here is that literally every organism on Earth has unique adaptations that make it suited to its habitat. That's essentially what evolution does. It is the process by which organisms develop traits that make them as well-suited to their habitats as possible. For freshwater fish in general, this involves things like different mineral processing and osmoregulation. They don't have any salt in their environment, so their organs evolved to not be able to process it well. Another adaptation that most fish have, including saltwater fish, is something called countershading. It's where the underside of an organism is lighter colored than the top of its body. That way, a predator looking from above will see a dark color that can blend in with the substrate or with the darker color of deeper water. A predator looking from below will see a lighter color that blends in with the light shining through the surface of the water.

If you are asking about specific aquarium fish, let me know and I can try to give examples for those species too.

Or maybe how did the fish evolve to become schooling fish?
Schooling fish evolved because being in a school makes a fish much safer from predators, especially if they are small (most schooling fish are small fish, you might have noticed). You may have heard about "safety in numbers" and that is exactly why schooling evolved. If there are large numbers of fish all in a group, it becomes much more difficult for predators to single out a fish from the group. If the school moves together in a pattern, the predator could also become confused. But, most simply, if you are a fish in a group, the chances of a predator selecting YOU, specifically, are much lower than if you were by yourself. Being in a group allows more fish to escape, even if the predator does get one or two fish.

How do fish communicate to each other? I don't hear most species communicating each other in my POV.
A lot of fish don't communicate using sound. There are also a lot of fish that do use sound, but we either can't hear it or don't choose to listen for it. Fish can also communicate visually. Their colors and patterns can be messages to other fish. Many species have the ability to change colors and that ability is often used to communicate with other members of its species. For example, bright coloration is often used to signal mating availability or territoriality to other fish. Subdued colors can signal submissiveness. Many fish also use pheromones to communicate a variety of messages and those are detected by scent.
 
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How do tetras and bettas adapt well in the wild and in the aquarium hobby?
I'm not sure about tetras. They are a very large group of fish and there's a lot of diversity in that group, so they also have a variety of different evolutionary strategies. However, most (if not all) of them are schooling fish, so that's one major adaptation.

Bettas are one of the interesting cases where many of the species evolved alongside humans. Rice paddies are a very excellent place to catch insects since they are shallow and without any water movement, so many insects will breed in those waters and are a great food source. Bettas evolved to take advantage of this habitat. They're small, so they can deal with the relatively small space found in rice paddies, and the wild-types have short fins for moving and darting quickly through the water, which is essential for catching insects. Rice paddies can have very poor oxygenation due to little water movement, so the labyrinth organ in bettas also helps them. Of course, other fish can breathe air too. Gouramis have the labyrinth organ (bettas are a type of gourami, after all) and corydoras can absorb air through their guts. However, even though the labyrinth organ or the ability to breathe air in general is not unique to bettas, it did allow them to take advantage of the oxygen-poor rice paddies when other fish couldn't.
 
I'm just a curious person and not a researcher. There are a couple of things I'd add to the excellent start above. Remember, you've asked a question that is really complex.
Fish don't evolve in straight lines. Life is more like a bush than a tree. The fish that others evolved from can still be there. A few members of the species become isolated from the others, and as they breed, they change. The short branches sometimes grow and sometimes die.
We're short lived creatures but the planet is old, and it's hard for us to get our heads around how old. In most cases, these processes take a very long time. Genes copy themselves, and the copies aren't perfect. Sometimes that means nothing, sometimes it is fatal, sometimes it means a lot. The world is dynamic, and everything is moving everywhere at the same time. A mutation can give an advantage, and if it does and the mutant individual is lucky, then he or she has more babies to inherit the mutation and it spreads.
Betta splendens are brown fish with a little red and blue so the males can be good looking to the females. Their fins are short, and they move very little, protecting a spot to catch bugs at, and maybe build a nest.
Ancient people noticed some males killed each other if they were put in tiny spaces together, and with us being nasty creatures, they began to gamble on the fights. They chose the most aggressive males, and in time, to make a better show, they began to breed longer finned and more colourful ones out of the random differences between individuals, while still trying to choose ones who showed maximum fighting ability. The Betta you see in a store is larger, longer finned, different coloured and more aggressive (sometimes) than a wild type, which can look like a different species of fish. Think wolf versus pug, and the human directed process to turn a wolf into a lapdog....
I don't know a lot about tetra evolution. It's tied into the ancient geology of the world, starting with before the continents broke apart. Tetras are in the Characin group, and related fish are found in Africa and the Americas. The same is true for Cichlids, and my beloved killies. Their story is really ancient, and started when those continents were still one body. It's taken some time for them to drift apart as far as they have..
You won't get any real understanding off postings in a fish forum. You need to get reading - plate tectonics, the history of our planet, genetics and how they work, ecology... Read about these things for 2 hours a day and check back in 20 years.
 
I'm just a curious person and not a researcher. There are a couple of things I'd add to the excellent start above. Remember, you've asked a question that is really complex.
Fish don't evolve in straight lines. Life is more like a bush than a tree. The fish that others evolved from can still be there. A few members of the species become isolated from the others, and as they breed, they change. The short branches sometimes grow and sometimes die.
We're short lived creatures but the planet is old, and it's hard for us to get our heads around how old. In most cases, these processes take a very long time. Genes copy themselves, and the copies aren't perfect. Sometimes that means nothing, sometimes it is fatal, sometimes it means a lot. The world is dynamic, and everything is moving everywhere at the same time. A mutation can give an advantage, and if it does and the mutant individual is lucky, then he or she has more babies to inherit the mutation and it spreads.
Betta splendens are brown fish with a little red and blue so the males can be good looking to the females. Their fins are short, and they move very little, protecting a spot to catch bugs at, and maybe build a nest.
Ancient people noticed some males killed each other if they were put in tiny spaces together, and with us being nasty creatures, they began to gamble on the fights. They chose the most aggressive males, and in time, to make a better show, they began to breed longer finned and more colourful ones out of the random differences between individuals, while still trying to choose ones who showed maximum fighting ability. The Betta you see in a store is larger, longer finned, different coloured and more aggressive (sometimes) than a wild type, which can look like a different species of fish. Think wolf versus pug, and the human directed process to turn a wolf into a lapdog....
I don't know a lot about tetra evolution. It's tied into the ancient geology of the world, starting with before the continents broke apart. Tetras are in the Characin group, and related fish are found in Africa and the Americas. The same is true for Cichlids, and my beloved killies. Their story is really ancient, and started when those continents were still one body. It's taken some time for them to drift apart as far as they have..
You won't get any real understanding off postings in a fish forum. You need to get reading - plate tectonics, the history of our planet, genetics and how they work, ecology... Read about these things for 2 hours a day and check back in 20 years.
I'm learning fish evolution because I'm curious about it.
 
I'm learning fish evolution because I'm curious about it.
Me too. I'll be learning it til the day I die and still will have barely scratched the surface. A lot of people are desperate for easy to follow answers in life, but you've asked yourself something that could take a lifetime. I was 12 when I saw a documentary on Galapagoes finches, and I've been on a quest ever since.
 
I agree with Gary. If you want to learn about evolution, I recommend finding books or documentaries. Forums will not be the best place to get the information you're looking for. Even though I have been taught extensively about evolution through my university degrees, I still don't have all the answers, especially for specific species of fish. I have a very solid knowledge of the theory of evolution in general, but even those who have that foundation of knowledge have limited time and energy for teaching. Evolution is a complex topic that takes a lot of time to learn and a lot of time to explain.

If you want to know about fish evolution, you must know the basics of evolution in general, for all organisms. Books will be the best resource for this information. Once you know the basics, then you will be able to understand the evolution of specific groups of organisms. Once you get to this point, you might want to try finding scientific papers. Most books about evolution in general will not talk at length about the evolution of specific fish species. Scientific papers which are focused on specific groups or species of fish will have more information. They can be dense and difficult to understand though, if you aren't used to reading them. That's the primary downside, but occasionally, you'll find a very well-written paper that uses more accessible language.
 
Fish evolution can be looked at through their family tree (phylogenetic tree for fish). Biology books often have a family tree for all living organisms and if you look at the branch dealing with fishes, you can follow individual species back along the tree to see what they might have evolved from.

Regarding rainbowfishes, I'm pretty sure Gerald Allen mentioned in one of his books they are a relatively new group of fishes that started after the last ice age (10,000 years ago). We believe they came from hardyheads because they have a lot of similarities and both are in the family Atherinidae. Hardyheads are basically bait fish like sardines and it'ssumed that a number of them got into freshwater bodies around the end of the ice age and turned into freshwater fishes we call rainbowfish. There are some that live in brackish and even sea water and they are probably more modern versions of their ancestors. However, a lot of marine fishes are very similar to their fossil ancestors from hundreds of millions of years ago. So whilst freshwater species have evolved over millions of years (or less for rainbowfish), most marine fishes haven't changed much if any during that time.



This is a good link that has a fish family tree including the salamanderfish

This has a similar tree
 
I do agree with Seisage, Colin and Gary.
It's not weird that freshwater fish came from salt water fish, for the water on this globe is mainly salt water. And don't forget that the continents were once all one big continent and was surrounded by salt water before it got divided in multiple continents.
About evolution: Most nowadays life forms have been subject to evolution. I've mentioned deliberately "most' for it's known that there are life forms that are still the same as when they first showed up. Evolution means adapting to cicumstances. Many life forms have been adapted by their environment. That could be caused by many things like food sources, temperature, landscape, light, etc...
With fish in general, it will be hard to go back that far. Unless, they find fossils or something else where they can extract DNA from.

I wrote an article once about the evolution of ornamental body parts in livebearers.
 
And finally, native fish I haven't heard of before. I heard of the salamanderfish before, but not the nightfish, a WA native. Have the nightfish been bred in captivity? What are some other natives I haven't heard about? I fear that the local government might do the wrong thing on the native fish again.
To the best of my knowledge, the nightfish (Bostockia porosa) have not been bred in captivity. They are difficult to keep alive and adult fish only eat live foods. If you collect baby nightfish, they usually starve to death. Young fish around 1 inch long tend to do the best in aquariums. However, they won't eat dry food and you normally feed them on frozen and live foods. They are prone to fungal infections and I used to find them sitting in their caves covered in fungus. They are also sensitive to chemical medications.

Other native fishes from the south-west of Western Australia include Galaxias occidentalis and G. truttaceus, Galaxiella munda and G. nigrostriata, the salamanderfish (Lepidogalaxias salamandroides), Balstons pygmy perch (Nanatherina balstoni), the common pygmy perch, the little pygmy perch (which was recently identified and classified by Dave Morgan from Murdoch Uni), and Tandanus bostocki (an eeltail catfish).

There are also native fishes found north of Perth and rainbowfish can be found from Carnarvon northwards. Spangle Perch can be found around Geraldton and north. Various hardheads can be found from Carnarvon northwards too.

--------------------

Galaxias occidentalis have been bred in captivity but not successfully reared up. The males and females look similar until breeding, the males are slimmer than females. The males start displaying to the females and part of the display is a dorsal blaze. This is a coloured stripe (yellow or white) that runs along the top of the head towards the mouth. The males flash this stripe on and off while displaying their fins. Rainbowfish also have a dorsal blaze, which is kind of interesting because these fish are nothing alike. Eggs were scattered among Java Moss in the aquarium and that was the end of the breeding. In the wild the fish will wait for a flood or high tide and lay their eggs in grass on the banks or next to the banks of creeks and rivers. They will also breed in algae in the wild.

Galaxias truttaceus have not been bred in captivity and are endangered in Western Australia due to introduced species of fishes being released into their habitat (the Goodga River in Albany). The fish are apparently also found in the King River in Albany but I never found any there and I looked for them numerous times over a number of years. These fish are really lovely when little and have black vertical lines on their body and red fins. As they get older the lines break up and become dots, and the red fins fade. They are pretty easy to keep in captivity but are prone to bacterial infections and other diseases from common aquarium fishes, so must be kept in a newly set up tank that has not had any introduced species in.

If collecting Galaxias for aquariums, the best sized fish are around the 2 inch length mark. They are small and narrow and jump so the aquarium must be well covered. The young fish will eat anything that floats on the surface and readily take to dry floating foods as well as frozen and live foods. The adults refused dry fish food but would take frozen and live foods.

An interesting thing about Galaxias from WA is their colour patterns. Every fish has different markings. The markings from related family members are very similar and might only vary by a single dot. Fish from different locations can have dots or lines, or dots and lines.

--------------------

Galaxiella munda and nigrostriata are lovely little fish about the size and shape of a match. They used to be common but have been wiped out by Gambusia, habitat destruction, chemical poisoning from pesticides and herbicides used on bushland and farms, and general pollution of their environment. G. munda is much more common than nigrostriata, which is almost extinct.

G. munda have bred in a pond (technically a 60? litre plastic storage container) but have not been bred in aquariums. I didn't do anything special for the ones in the tub. They had an AquaClear HOB filter on the container and were fed dry fish flakes and frozen fish foods each day. They got newly hatched brineshrimp and microworms too. Their container was outdoors under shadecloth and in a garden where there were lots of small flying insects (mosquitos by the millions). The fish were put in the container and 12 months later there were more than i had originally collected. I didn't see any breeding but they obviously did.

There is very little known about Galaxiella nigrostriata from an aquarium standpoint or even in the wild. A member that came on here (Forest), can't remember his user name, was interested in them and managed to get some but I have not heard from him for a while.

There is a third species of Galaxiella that has not been described and I only found it once. It was a cream coloured fish with a black head and a light blue sheen over the dorsal half of the body. They were about 2 inches long and slightly thicker in the body than G. munda and G. nigrostriata. I found them in a stormwater ditch next to the road between Walpole and Northcliffe. I didn't take any at the time and some years later when I was back down there, I was unable to find them.

--------------------

Lepidogalaxias salamandroides is from the south-west of Western Australia and grows to about 75mm. They live in water with virtually no mineral content and a very low pH (between 3.0 & 6.0). They are a prehistoric species and the only species of fish that can turn its head independently of its body. This is an adaptation to them burrowing into the mud and aestivating during the dry summer period. The fish produces a mucous cocoon around their body at the bottom of their burrow and wait out the dry period. If the fish has not built up sufficient weight before aestivation, it won't survive the summer.

Males and females have different shaped anal fins. They have not been bred in captivity.

In aquariums these fish will take live and frozen fish foods but do not touch dry food.

These fish are going to become extinct due to habitat destruction and climate change, in particular, a drying climate with less rain. Habitat destruction is mainly caused by the WA Department of Transport making the roads wider and covering up the ponds where the fish live.

--------------------

I have kept all 3 species of WA pygmy perch (little, normal and Balstons). The normal and little are incredibly easy to keep and look the same apart from a slight difference in size and eye shape. However, you need all 3 species in the same tank to be able to easily spot the difference. I caught the little ones before they were identified as a new species and they ended up mixed in with some normal pygmy perch that ended up wherever (can't remember). The Balstons pygmy perch went over east with some other fish.

The normal pygmy perch is easy to keep and breed. They eat anything, love well planted aquariums, and breed right through the warmer weather. Female fish produce a few eggs each day and the adults don't normally eat the eggs or young if they are well fed.

Balston's pygmy perch were more fussy about food and readily took frozen and live foods but didn't touch dry food. I didn't breed these fish.

--------------------

Tandanus bostocki is an eeltail catfish that grows to 18 inches long, but is more commonly seen around 8-12 inches long. They aren't normally kept in aquariums due to their size and needing to be kept in groups. Adult fish are often seen foraging alone at night but young fish live in groups. They eat most frozen or live fish foods that sink to the bottom.

Eeltail catfish have an eel shaped tail vs forktail catfish that have a tail like a normal fish.

These fish aren't a commercial food fish and are too big for aquariums. There is little known about them but they are declining in numbers, presumably due to chemicals/ pollution in the water. As a kid we used to go fishing for these in the local creeks. We used a handline and small hook with a bit of meat on it. They were tasty fish but hard to handle because they are slippery.
 
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I do agree with Seisage, Colin and Gary.
It's not weird that freshwater fish came from salt water fish, for the water on this globe is mainly salt water. And don't forget that the continents were once all one big continent and was surrounded by salt water before it got divided in multiple continents.
About evolution: Most nowadays life forms have been subject to evolution. I've mentioned deliberately "most' for it's known that there are life forms that are still the same as when they first showed up. Evolution means adapting to cicumstances. Many life forms have been adapted by their environment. That could be caused by many things like food sources, temperature, landscape, light, etc...
With fish in general, it will be hard to go back that far. Unless, they find fossils or something else where they can extract DNA from.

I wrote an article once about the evolution of ornamental body parts in livebearers.
I'll have to make a slight correction here! It's an extremely common misconception that some organisms have stopped evolving, and that is not the case. Everything is constantly evolving and always has been, it's just that rates of adaptation development and species divergence are different between different groups of organisms. It's true that some organisms like sponges, ctenophores, and archaea are extremely similar to their ancestors. They happened to find a body plan and life strategy that worked extremely well for them, so there's not much need to change, but evolution is still happening for these groups since new species consistently develop and diverge, even in relatively recent geologic history. It's the same sort of concept as with chimpanzees and humans. Humans did not evolve from chimpanzees or any other modern ape. We evolved alongside each other from the same common ancestor, which no longer exists, so we are just as evolved as chimpanzees. That's true of every living thing. Every species on Earth is just as evolved as all the rest because evolution is constantly happening to all of us.

I personally think that's one of the most fascinating things about evolution. Everything is always changing and developing, even if it doesn't look like it. And, I think it is interesting when nature finds a way of being that is so successful that it sticks around for millions of years despite evolution's unending march. Inverts and microbes aside, even consider sharks and crocodiles. Of course, the species we have today were not the ones we had tens of millions of years ago, so they are still evolving, but they look largely the same as their ancestors because they're an incredibly successful type of organism.
 
This might be of some interest to those following this thread, but I recently found a Youtube channel called Freshwater Ichthyology. It's run by a woman named Rebecca who's a PhD candidate studying the evolution of plecos and other Loricarids (but mostly plecos). She's also a fishkeeper herself. She makes a lot of videos about plecos, of course, but also a few about general aquarium care and other fish species.

I haven't watched a lot of her videos yet, but she seems like a very good source to learn about Loricarid evolution from.
 
To the best of my knowledge, the nightfish (Bostockia porosa) have not been bred in captivity. They are difficult to keep alive and adult fish only eat live foods. If you collect baby nightfish, they usually starve to death. Young fish around 1 inch long tend to do the best in aquariums. However, they won't eat dry food and you normally feed them on frozen and live foods. They are prone to fungal infections and I used to find them sitting in their caves covered in fungus. They are also sensitive to chemical medications.

Other native fishes from the south-west of Western Australia include Galaxias occidentalis and G. truttaceus, Galaxiella munda and G. nigrostriata, the salamanderfish (Lepidogalaxias salamandroides), Balstons pygmy perch (Nanatherina balstoni), the common pygmy perch, the little pygmy perch (which was recently identified and classified by Dave Morgan from Murdoch Uni), and Tandanus bostocki (an eeltail catfish).

There are also native fishes found north of Perth and rainbowfish can be found from Carnarvon northwards. Spangle Perch can be found around Geraldton and north. Various hardheads can be found from Carnarvon northwards too.

--------------------

Galaxias occidentalis have been bred in captivity but not successfully reared up. The males and females look similar until breeding, the males are slimmer than females. The males start displaying to the females and part of the display is a dorsal blaze. This is a coloured stripe (yellow or white) that runs along the top of the head towards the mouth. The males flash this stripe on and off while displaying their fins. Rainbowfish also have a dorsal blaze, which is kind of interesting because these fish are nothing alike. Eggs were scattered among Java Moss in the aquarium and that was the end of the breeding. In the wild the fish will wait for a flood or high tide and lay their eggs in grass on the banks or next to the banks of creeks and rivers. They will also breed in algae in the wild.

Galaxias truttaceus have not been bred in captivity and are endangered in Western Australia due to introduced species of fishes being released into their habitat (the Goodga River in Albany). The fish are apparently also found in the King River in Albany but I never found any there and I looked for them numerous times over a number of years. These fish are really lovely when little and have black vertical lines on their body and red fins. As they get older the lines break up and become dots, and the red fins fade. They are pretty easy to keep in captivity but are prone to bacterial infections and other diseases from common aquarium fishes, so must be kept in a newly set up tank that has not had any introduced species in.

If collecting Galaxias for aquariums, the best sized fish are around the 2 inch length mark. They are small and narrow and jump so the aquarium must be well covered. The young fish will eat anything that floats on the surface and readily take to dry floating foods as well as frozen and live foods. The adults refused dry fish food but would take frozen and live foods.

An interesting thing about Galaxias from WA is their colour patterns. Every fish has different markings. The markings from related family members are very similar and might only vary by a single dot. Fish from different locations can have dots or lines, or dots and lines.

--------------------

Galaxiella munda and nigrostriata are lovely little fish about the size and shape of a match. They used to be common but have been wiped out by Gambusia, habitat destruction, chemical poisoning from pesticides and herbicides used on bushland and farms, and general pollution of their environment. G. munda is much more common than nigrostriata, which is almost extinct.

G. munda have bred in a pond (technically a 60? litre plastic storage container) but have not been bred in aquariums. I didn't do anything special for the ones in the tub. They had an AquaClear HOB filter on the container and were fed dry fish flakes and frozen fish foods each day. They got newly hatched brineshrimp and microworms too. Their container was outdoors under shadecloth and in a garden where there were lots of small flying insects (mosquitos by the millions). The fish were put in the container and 12 months later there were more than i had originally collected. I didn't see any breeding but they obviously did.

There is very little known about Galaxiella nigrostriata from an aquarium standpoint or even in the wild. A member that came on here (Forest), can't remember his user name, was interested in them and managed to get some but I have not heard from him for a while.

There is a third species of Galaxiella that has not been described and I only found it once. It was a cream coloured fish with a black head and a light blue sheen over the dorsal half of the body. They were about 2 inches long and slightly thicker in the body than G. munda and G. nigrostriata. I found them in a stormwater ditch next to the road between Walpole and Northcliffe. I didn't take any at the time and some years later when I was back down there, I was unable to find them.

--------------------

Lepidogalaxias salamandroides is from the south-west of Western Australia and grows to about 75mm. They live in water with virtually no mineral content and a very low pH (between 3.0 & 6.0). They are a prehistoric species and the only species of fish that can turn its head independently of its body. This is an adaptation to them burrowing into the mud and aestivating during the dry summer period. The fish produces a mucous cocoon around their body at the bottom of their burrow and wait out the dry period. If the fish has not built up sufficient weight before aestivation, it won't survive the summer.

Males and females have different shaped anal fins. They have not been bred in captivity.

In aquariums these fish will take live and frozen fish foods but do not touch dry food.

These fish are going to become extinct due to habitat destruction and climate change, in particular, a drying climate with less rain. Habitat destruction is mainly caused by the WA Department of Transport making the roads wider and covering up the ponds where the fish live.

--------------------

I have kept all 3 species of WA pygmy perch (little, normal and Balstons). The normal and little are incredibly easy to keep and look the same apart from a slight difference in size and eye shape. However, you need all 3 species in the same tank to be able to easily spot the difference. I caught the little ones before they were identified as a new species and they ended up mixed in with some normal pygmy perch that ended up wherever (can't remember). The Balstons pygmy perch went over east with some other fish.

The normal pygmy perch is easy to keep and breed. They eat anything, love well planted aquariums, and breed right through the warmer weather. Female fish produce a few eggs each day and the adults don't normally eat the eggs or young if they are well fed.

Balston's pygmy perch were more fussy about food and readily took frozen and live foods but didn't touch dry food. I didn't breed these fish.

--------------------

Tandanus bostocki is an eeltail catfish that grows to 18 inches long, but is more commonly seen around 8-12 inches long. They aren't normally kept in aquariums due to their size and needing to be kept in groups. Adult fish are often seen foraging alone at night but young fish live in groups. They eat most frozen or live fish foods that sink to the bottom.

Eeltail catfish have an eel shaped tail vs forktail catfish that have a tail like a normal fish.

These fish aren't a commercial food fish and are too big for aquariums. There is little known about them but they are declining in numbers, presumably due to chemicals/ pollution in the water. As a kid we used to go fishing for these in the local creeks. We used a handline and small hook with a bit of meat on it. They were tasty fish but hard to handle because they are slippery.
Interesting fish! How did you manage to save some of the species mentioned from extinction?
Me too. I'll be learning it til the day I die and still will have barely scratched the surface. A lot of people are desperate for easy to follow answers in life, but you've asked yourself something that could take a lifetime. I was 12 when I saw a documentary on Galapagoes finches, and I've been on a quest ever since.
I like learning about fish, but evolution can take it to a whole new level.
 

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