Interbreeding Corydoras

[Akasha72]

Hi everyone, this is a subject that's cropped up elsewhere and as I don't want to hyjack someone else's thread I thought I'd bring any possible dicussion here - apologies if we've had a similar thread in the past - I only came back to this forum this week after a long break.
 
 
So here's what's started my brain ticking... I have several cories - 8 peppered, 5 bronze 6 panda's and now three new melini cories (hoping to increase their number today). When I added the melini's one went straight to a panda female and did the little waggle in front of her which I've come to know as a spawning invitation. Seeing this set me off trying to find out if the panda's can interbreed with melini. After a bit of research and a couple of posts on other forums I got my answer ... yes they can interbreed. Out of all the cory types it would seem the panda is the most prolific interbreeder.
 
Now my panda's have now got into the habit of spawning in a secluded spot in the plants which means I have baby panda's popping up on a regular basis now (I started out with 4 panda's but now I have at least 6 - there could be more hiding though) and so I asked my lfs if I could bring them any more that 'pop up' but also warned them that I have 3 young melini and that they could interbreed with my panda's and so any fry I bring could be hybrids.
Their answer was 'no problem, if we suspect a hybrid they can go into the display tank and not for sale' but a few days later when back at the lfs to buy some food I got chatting to the owner about the possibility of my panda's interbreeding with the melini and the possibility of me bringing him hybrid fry.
His take on it was different .... his take was - they live in large groups in the wild and if they can interbreed in a tank they can interbreed in the wild and how can we know for certain if all the different cory types havn't appeared through interbreeding.
 
It has got me thinking. 
 
Now my new melini have been mistaken for bandit cories but the bandit has some orange markings (if I'm not mistaken) but these melini's are pure white with the black stripe over the eyes (the same as the panda has) and the black diagonal line running through the dorsal to the bottom fork of their tail. I have seen them labelled online as 'false bandit' also. But whilst I was talking to the lfs owner he was showing me all the different cards that they stick to their tanks with a photo of the fish and it's requirements. Within 10 minutes on the desk there were about 6 different cards all with a different cory but all very similar. Which begs the question to me .... if the Panda cory is a prolific interbreeder is that where all these similar looking cory species has come from?
 
What do we think?

 

[Lillefishy]

I would not allow hybrids to get into the trade at all, it causes confusion when trying to identify them & does nothing to help the species.
If corys are kept in large enough groups hybridisation rarely happens as there are enough of their own species to breed with
In the wild they live in large shoals & many of the species we keep in aquariums would never come across each other in the wild.
If your corys are hybridising I would remove them & keep the species separate or keep species together that cannot hybridise.

 

[Akasha72]

yes, I would agree Lilliefishy and this was my reason for hunting down some more melini cories so that once they are old enough to breed they keep it to their own species ... unfortunately the lfs didn't have any but I fully intend to keep looking. Unfortunately I no longer have the space for another tank and so seperating the panda's and melini isn't an option.
 
Your response hasn't really answered my query though (which is fine) 
 
If the panda cory is a prolific interbreeder is that where some of the similar looking cories have originated from? And also ... someone please correct me if I have this wrong ... but the gold and green laser cory ... isn't that a hybrid of the bronze cory?

 

[Lillefishy]

Gold & green laser corys although in the aenus family aren't hybrids.

 

[Akasha72]

Gold & green laser corys although in the aenus family aren't hybrids.

 
 
I was misinformed then ... many thanks for correcting me
 
There's always something new to learn in this hobby which is partly my reasoning for this thread  

 

[TwoTankAmin]

I suggest you take a look over on planet catfish about this issue. Some interesting info there from some very well know cory breeders/keepers.
 
http/www.planetcatfish.com/forum/viewtopic.php?f=6&t=29730&hilit=cory+interbreeding
 
http/www.planetcatfish.com/forum/viewtopic.php?f=6&t=19885&p=111965&hilit=cory+hybrids#p111965
 
http/www.planetcatfish.com/forum/viewtopic.php?f=6&t=39477&p=270273&hilit=cory+hybrids#p270273

 

[Akasha72]

Thanks TTA - I got the info regarding my panda's and melini on planet catfish. I trust their judgement and advice there
 
 
 
Can I just say ...
 
I have no intention of purposely interbreeding my cories and the thought of them interbreeding doesn't sit well with me. It's not something I agree with but if it happens there is nothing I can do to stop it. If I suspect they have interbred without my knowledge then any fry will be passed to my lfs with the full knowledge of what they are. What they then choose to do with the possible hybrid fry is their choice.
I started this thread because I didn't want to hyjack another members thread and the talk on there was heading in that direction. It was just to throw open the main question which I've repeated twice now - if they interbreed in the tank then is there the chance they're interbreeding in the wild and is that why there are so many similar cories.
I'm not trying to start any arguements ... I'm purely curious 

 

[Akasha72]

the cory man on planet catfish has put my mind at rest. The new melini's are a mix of male and female from what I can tell (trying to get a good view of their fins isn't easy but I'm guessing two female and one male at the moment) and my panda's are a mixture of male and female too. From what The Cory Man is saying the chances of my panda's and melini cross breeding is very very slim ... phew!

 

[Lillefishy]

 
 
 
If I suspect they have interbred without my knowledge then any fry will be passed to my lfs with the full knowledge of what they are. What they then choose to do with the possible hybrid fry is their choice.

Theirin lies the problem, you take your hybrids to the Lfs & let's be honest they won't really care who they sell them to, it's just a sale for them.
Those hybrids then breed & that owner takes the fry to an Lfs, they get sold, breed etc & the genes of those hybrids get spread around.
Please do not let hybrids get into the trade.

 

[fluttermoth]

To answer your original question; it's very, very unlikely that wild fish will interbreed. Usually fish become speciated (that's evolve into different species) because they're physically separated from each other. If times change, and they come onto contact, they're often so diverged that they can no longer interbreed.

In the wild, fish would be very unlikely to meet another species that it's possible to interbreed with; this really only happens in our tanks.

The reason many cories have similar patterning, is through covergent evolution; the same markings benefit all the fish that have them in the same way. For example, having a dark stripe over the eyes (to make the eyes less easily seen by predators) is a feature that's seen in very many fish. The 'eye spot' on the caudal peduncle (which can make predators go for the 'wrong' end of the fish in an attack) is also very common, seen in fish as different as the oscar and dwarf emerald danios.

 

[Byron]

I posted a lengthy response in the other thread, before seeing this present one, so I will just copy the text over.  Much if not all of this has been said or hinted at, but I put some effort into that response and don't want to lose it.

 
Before I respond to your question about the species, I must say that it is sad to hear that your store is willing to take in possible hybrids; this is something that we as hobbyists should never condone or encourage.  Keeping pure strains of fish is extremely important biologically, environmentally and ecologically.  Although not likely to be needed in the case of panda corys, there are other species of tropical fish that are extinct or close to extinction in nature, and aquarium fish could well be the source of re-introduced species.  It is one thing to confine experimental hybrids to one's aquarium, but quite another matter to release it to the hobby.  Enough on that, now to your species.
 
Hybridization among corys in their habitats is very probably non-existent.  For one thing, the species rarely mix, and even when they are known to, cross-breeding has never been documented.  When we confine fish to the very small and enclosed space of an aquarium, they can be affected in ways that would absolutely never occur naturally.  Sometimes the offspring are sterile, which is one way of nature telling us it is not "natural," as such fish would never survive in the wild but die out.  But in terms of geography, many species of cory, especially those now being discovered for the first time, are endemic to one specific stream or creek, and found no where else.  Each of these species descended from ancestors, and this is where we get into phylogenetics.  As for the many species, this is an example of Darwin's discovery of natural selection at work.  And it is occurring with many different Amazonian species besides corys.  You can be assured that these new species are not hybrids, and phylogenetic analysis confirms this.
 
Phylogenetic analysis became possible after the discovery of DNA in (I believe) the 1970's, and over the past two or three decades has become more and more standard as part of the process in describing species.  Phylogeny is sometimes referred to as the natural relationships and is an attempt to construct the history of all life based on the evidence from both living and fossil organisms. This allows us to trace a fish back to its original ancestor.  Fishbase lists 159 valid species in the genus Corydoras, and new species are being discovered and described regularly.  Phylogenetic analysis allows ichthyologists to ascertain just where each of these species fits.
 
A genus (plural genera) is a grouping of one or more species that share identical properties.  Prior to the discovery of DNA and development of phylogenetics, ichthyologists used physical characteristics to classify species into genera.  Dentition was a major factor, along with fin ray numbers, internal physiological characteristics such as bone structure, and so forth.  Outward appearance was considered but was often of less importance.  Thinking only of corys, all species in the genera Aspidoras, Corydoras and Brochis have the same general appearance, and they also share a number of identical characteristics beyond this.  These genera are thus classified in a family, here known as the Callichthyidae [family names always end in "dae"].  But because there are many other species that share these characteristics but also have significant variances, the family was divided into subfamilies, and our corys and their closest cousins are in the subfamily Corydoradinae [subfamilies end in "nae"].
 
With the benefit of phylogenetics, we now see that some of these fish are not so closely related, in spite of their general outward appearance, but certain others are.  Thus, we have suggestions that instead of three genera, there should be nine.  Brochis as I mentioned previously has already been invalidated as a distinct genus.  In spite of their different physical characteristics--"brochis" fish are larger with a rather higher profile, and the dorsal on the three Brochis species has between 10 and 18 rays, while on all "corydoras" species it has 6 to 8 rays--the three species are now Corydoras.  As you can see, in the new classification these outward physical characteristics are not of prime significance in classification.
 
The present genus Corydoras with its 159 species is termed polyphyletic because all of the species did not descend from the same common ancestor, and conversely all of the descendants of an individual ancestor are not included.  Classification now aims for monophyletic genera, which is a taxon (group of organisms) that forms a clade, meaning that it consists of an ancestral species and all its descendants.
 
The variety of "cory" species, many having very similar colour patterns, all evolved independantly from some ancestor.  Allopatric speciation, also termed geographic speciation, occurs when populations of a species become isolated, to the degree that influences or prevents genetic interchange.  Distinct species, or sometimes subspecies, may occur; or the species may remain basically intact genetically and form variants.  This has occurred with many fish, especially those that have a widespread range.  The Blackwing Hatchetfish, Carnegiella marthae, is now known to have at least three cryptic species, but further sampling will be required before ichthyologists can be certain these are variants (as presently held), subspecies or distinct species.  This is what seems to have occurred with many of the species now being discovered as collectors enter areas of the rainforest previously never explored, at least for fish.
 
This has been lengthy, but feel free to question and I will do my best.
 
Byron.

 

[Akasha72]

Fluttermoth and Byron .... Thank You .... thank you for explaining what I wanted and needed to know without judgement on my ignorance. 
 
 
When I saw the three melini I thought they were panda's and I was about to walk on by but then one turned around and I saw the black stripe. I'd never seen cories like them in my area before and because I like to buy fish that are a little unusual I got the remaining three and the staff member told me what they were. At this point, and as far as I was aware at the time, cories only bred within their own species. It was only when the melini's were added and one invited spawning with a female panda that I discovered (through asking on planet catfish) that the two species could interbreed.
By then the deed was done and I was not about to pull my tank apart trying to catch 3 fish to return them. I don't buy fish to return them because they don't suit my purpose. I'm also soft hearted and I was feeling rather attached to them ... I still am. I now intend to add to the melini numbers and hope that if spawning ever occurs they keep it with in their own family.  
 
Thanks also to the rest of you for your input ... and hi Fluttermoth - another name I recognise from 'the old days'

 

[fluttermoth]

Thanks for the great post, Byron; you said everything I was trying to say myself, but in much better detail

Hi Akasha; nice to see you back

Byron's new here, but he's been a great help to many already; we're very lucky to have such a knowledgeable fishkeeper on the forum

 

[Akasha72]

yeah .. I'm already seeing his posts are great. I wish I was as knowledgable and could put my point across as well! I've not changed ... I still waffle too much lol

 

[Byron]

I would like to thank you (fluttermoth and akasha) indeed for your kind words, they are very much appreciated.
 
I normally restrict my activity to topics on which I have made a serious study, and species and habitats is prime.  These are sometimes ignored by beginning aquarists who view them as "scientific" and not practical, but the truth is that one will have far greater success with an aquarium if one understands the requirements and both the positive and negative aspects of every species.
 
I hope I can benefit by contributing.  And Akasha, I will never judge anyone's knowledge, and you are certainly not ignorant.  Asking questions and listening to the response is a sign of intelligence; this is how we all learn.  We would still be sitting in caves rubbing sticks together to make fire if we didn't learn from others.
 
Byron.