smaller fish that thrive well in bigger tanks...

[Magnum Man]

just curious what smaller fish, you have found to thrive well??? I have a lot of Tetras, but admit, that while many are thriving, the smaller species have always not lasted like I've hoped... I've always wanted a big shoal of neons, or cardinals... I need to move an angel fish out of my Tetra tank before I try again, as it actively hunts smaller brightly colored species... but of the dozen jumbo cardinals I bought a while back, I'm down to one, that seems to be doing well, hanging with my Rummy Noses, and other assorted larger Tetras... in my Hillstream tank, I have several varieties that are just over an inch long, and the panda loaches I added recently, being a smaller variety, came in tiny ( just over yolk sack age ) and all of them have been growing and thriving, even though they are in with many larger fish... so what are some of the smaller fish, that you have had long term luck with, in community tanks???

 

[elephantnose3334]

just curious what smaller fish, you have found to thrive well??? I have a lot of Tetras, but admit, that while many are thriving, the smaller species have always not lasted like I've hoped... I've always wanted a big shoal if neons, or cardinals... I need to move an angel fish out of my Tetra tank before I try again, as it actively hunts smaller brightly colored species... but of the dozen jumbo cardinals I bought a while back, I'm down to one, that seems to be doing well, hanging with my Rummy Noses, and other assorted larger Tetras... in my Hillstream tank, I have several varieties that are just over an inch long, and the panda loaches I added recently, being a smaller variety, came in tiny ( just over yolk sack age ) and all of them have been growing and thriving, even though they are in with many larger fish... so what are some of the smaller fish, that you have had long term luck with, in community tanks???

Not a community tank, but my silvertip tetras are doing well in a 3ft long 39 gallon aquarium. I have a journal on it if you want to view it:

148.6L (39.2 gallon) aquarium journal

I'm writing a journal about my newest aquarium- a 3ft long 39 gallon brought from a LFS and I can't wait to make it a good home for my remaining silvertip tetras. They have been in the old 10 gallon tall for nearly two years, so I am yet to put them in the 39 gallon once it's cycled and properly...

www.fishforums.net

 

[GaryE]

There's a twist. My 6 foot/2metre tank has only small fish, and they thrive. It's all tetras and Cory group species, and nothing else. Small fish can thrive in any sized tank, as long as they only share the space with small fish. Add any fish several times their size, and tank size then only matters if it's too small.
I have a small group of Axelrodia risei, ruby tetras, and are surviving, look good and are in colour, but they are intimidated by tetras like my peaceful black neons. I have no idea how I could catch the rubys in that jungle of a tank, but I probably should have kept them out of there, because even their peaceful tankmates are double their size.

My formula is that fish size matters. Large tank size doesn't.

 

[seangee]

Bigger is such a subjective word . But I do agree with @GaryE about similar size and temprement. I have 30-40 cardinals in a 1m tank. I have not added any since 2018 so I guess they are doing OK (I had around 60 back then but happy to ascribe the losses to natural causes). Main tank mates over the years have been glowlight tetras, cories, pencilfish and more recently lambchop rasboras. I am considering swapping the rasboras for the ember tetras I have in another tank so I can call this one an SA tank, at least in terms of fish , but I would like to breed the embers first as 7 of them would be lost in a tank this size. Today I have a group of juvenile bronze cories in there, I know they will end up bigger but I'm not expecting any impact from those. My only larger fish is my BN female.

 

[Back in the fold]

I tried Neon Tetra’s with Angelfish . ONCE . ‘nuff said .

 

[Uberhoust]

I have a single ember tetra that has lived with my angels for over 2 years now. It wasn't by design; he got caught up in a transfer and I couldn't catch him once he was in the big tank. The angels so far have left him alone.

More to your question, the best luck out of the tetra group I have had is with the Black Neons, they are not the smallest tetra and seem pretty robust, I lost my last one about 6 months ago but he was 8 or 9 years old. That said I am not a real fan of tetras because they don't interact with me like the cichlids do, though some are quite pretty.

 

[Innesfan]

I agree with @GaryE. Tank size is not germane. That said, some small species are generally longer lived than others. Cardinals are not known for longevity. Some have proposed that in the wild they are an annual species.

On the other hand, my tiny Brevibora dorsiocellata (Emerald Eye Rasboras) live for years and years. A large school of them--and they tightly school--with their flashing green eyes all aglow--is a pretty sight. My Nannostomus unifasciatus commonly make it to 7 years. Others in the genus also have a firm grasp on life but the 'unis' always outlast them. Many of the rhomboid shaped tetras--Lemons, Rosies, Garnets, Pristella, Von Rios, etc--also are in it for the long haul in my experience. I never had a neon or cardinal last that long. Three years is usually the outside limit.

 

[Jinx_]

All fish thrive in big tanks, give that you don't overstock too crazily

 

[Magnum Man]

that is actually not completely true... and actually the smaller the fish, it seems the more critical ALL the parameters become... I'm just beginning to be able to find small fish, that thrive, almost none would, with my "rock hard" well water... so, then I was running almost pure RO water... there were some, that still didn't seem to thrive, add almond leaves... still no luck, on some fish, now that I'm adding back a small portion of hard well water, I seem to be having the best luck so far, I just have to be careful, with the well water, living in an agricultural area, I'm sure there are nitrates in my well water...

then there are some people that seem to have good luck with Cardinals, mine don't all die, only "most", then comments from @Innesfan ( and he seems knowledgeable ), and says... "Cardinals are not known for longevity. Some have proposed that in the wild the are an annual species."

which makes me wonder, if some of these short life problems are not my tanks, but those fish... and that some that claim no issues, either aren't keeping accurate death rate counts, or have somehow found the magic needed for those small fish to thrive... my South American Tetra tank has many thriving species... some just don't seem to last long, while other live for years...

 

[Uberhoust]

which makes me wonder, if some of these short life problems are not my tanks, but those fish... and that some that claim no issues, either aren't keeping accurate death rate counts, or have somehow found the magic needed for those small fish to thrive... my South American Tetra tank has many thriving species... some just don't seem to last long, while other live for years...

As a generalization, in a number of organisms the smaller species with higher reproductive rates live shorter lives. In their natural environment they tend to be predated on at a high rate, as long as they reproduce fast enough there is no evolutionary advantage to living longer. I believe cardinals fall into this category, where the average life expectancy is low due to predation and their water ways drying out. You can get long lived individuals but after the fish's main growth and reproductive stage they don't have the genetic mechanisms to fight off infections, repair tissue, or repair genetic damage. I suspect a number of tetras follow this kind of pattern.

In my opinion I would suggest that a number of fish keepers have killed more fish than they would be willing to admit. Just human nature.

 

[anewbie]

I have around 30 n. epesi in a 65; however you are leaving too many fill in the blanks. I've had 20 caridnals in a 120 for 5 years with angel fishes; My largest current school is probably 40 serpae tetra in a 600 with chocolate cichild.

Conversely i think the rummy nose are having problems with the geo d (they are in the 500). I have 30 n. marylin in a 95 - lovely fish that does well in a strongly planted enviornment with a few 2-3 inch dwarf cichild (in this case they are with the winkelfleck but i have around 15 or 20 in there but only 4 full size adults.

In a 100 i have 20 emerald rasbora (a fantastic fish that does well in a dark aquarium). All of these aquariums 'cept the 120,600 and 500 have ec below 35 - the 600 and 500 are around 110 and the 120 is 240. ec is 2x tds so 240 ec is approx 120 tds.

 

[seangee]

then there are some people that seem to have good luck with Cardinals, mine don't all die, only "most", then comments from @Innesfan ( and he seems knowledgeable ), and says... "Cardinals are not known for longevity. Some have proposed that in the wild the are an annual species."

Most of my SA fish get pure RO water with nothing added, except liquid ferts in very small doses. Cardinals are known not to deal well with excessive minerals. When I kept them in my rock hard tap water (which also has nitrates at 50ppm) they were pretty much an annual fish. They get a 75%+ water change most weeks. This is the pic I posted last weekend of my cardinal tank after draining and before refilling. I did not forget to remove the hose - that's how much water I change every week. I don't bother too much about temp matching as long as the tank ends up within 3-4 C of the original temp - so its just the finger test. Not saying that's the magic formula but there is no way they have produced any fry in a community tank, full of cories and MTS, where the lights come on every day.
They are also massive and far brighter than any I have ever seen in a fish store around here.
I would describe them as hardy, robust fish that only require clean water. I have mentioned elsewhere that I am probably a chronic under feeder - I have no idea if that's a contributing factor. I keep thinking its time to add 20-30 little ones because I know they must be nearing the end of their lives - but for now I'm reluctant to mess with the balance of this tank. And I have no QT available.

Gratuitous bonus pic of the tank when its not empty taken a couple of weeks ago.

 

[Jinx_]

In my opinion I would suggest that a number of fish keepers have killed more fish than they would be willing to admit.

Very guilty here

 

[GaryE]

I once had a power blackout in winter that wiped out a shoal of robust, healthy cardinal tetras I had bought 7 years before. I would love to have seen how long they could have lived for. They looked great the day before the room got too cold for them.
Our aquariums are very unnatural. No predators, relative stability, easy access to food. I'm like @seangee in that I would be seen as an underfeeder by some. I change water regularly, religiously. These fish lived in a 75 gallon tank, with many fewer fish than the industry stocking calculators suggest.
I bred some cardinals last year, and so I know when they got started. I hope to see how long they live for, if I can outlast them. I have been responsible for some short fish lives, but as I've gained experience and perspective, used larger tanks, stocked more thoughtfully and learned to avoid overfeeding, fish are living long. Yeah, I have killed more fish than an angler. A lot more. My early tanks with no water changes make me cringe when I think of them.
For anyone who cares to learn, there is a lot of info out there, and a lot of people willing to share successes and failures. I think it's important to let go of some ideas - one being that small fish find living with occasional predators like angels okay. In nature, they avoid them when they can, and the Amazon doesn't have corners they can be trapped in. Small fish should live with small fish, and none should be disposable life. That neon deserves as much care as that Discus.
Mixed species communities take thinking through much more than tanks with a few larger fish. We tend to think it's the opposite, but those small ones are evolved to evade. They often live by taking to the shallows, tangles of roots, temporary habitats, flooded forests and other extreme environments. Extreme means specialized in evolution, and specialized can mean not very adaptable anymore. They've already adapted to thrive in places larger fish would die in, and we can't expect them to have the tools to thrive in overcrowded community tanks with fish several times their size.