Nobody is trying to tell you what to actually do with the fish, with either keeping them in your colony of corys or selling to a fish shop. But we are politely voicing our concerns and there are issues with hybrids especially when an unwitting person ends up with either deliberately bred or accidental hybrids.
In the past such threads about the pros and cons of hybrids have been locked and deleted because the comments got out of hand or certain impartial people didn't like/ agree with the topic in general. I believe such topics need to be addressed, and what better way then in a mature manner where experiences and personal knowledge can go a long way in helping other pet keepers and help them make informed choices.
I am sure you are aware that I keep quite a few birds (as well as fish) and for this I will use bird hybrids for my answers (and to some degree fish). In Australia it is all but impossible (and ridicously expensive) to import birds, so many of the imported species (prior to quarrentine crack downs) are the only breeding stock of certain species and even some of these are dying out in the trade. Take Red Cheeked Cordon Bleus for example, hens are natourisly hard to get so some unscruplous breeders to make a quick buck and to sell off spare Red Cheeked Males, sold pairs of Red Cheeked Male Cordon Bleu finches "paired" with a male all blue cordon bleus (this scam worked well especially if the blue males where still not in full adult plumage). In some cases they did pair a female blue with a Red Cheeked, and the out come unbeknown to the future breeder is going to be a hybrid. This innocent breeder then sells off the offspring in their mind as being male Red cheeked (if they end up showing it) or as female Red Cheeked Cordon Bleus, because after all that was what they originally purchased and never mixed their Cordon Blues with other ones.
Don't for a second think I am saying all breeders are dodgy and out for the quick dollar. But now I will put a twist in the saga. Say in all honesty you take your possible hybrids to a fish shop and are up front and honest about the possible hybridisation of the corydoras. You tell this to either the shop owner or one of the staff that is allowed to make purchases, BUT what if the message never gets passed on? Because people forget or suddenly other customers in the shop want assistance with something before any real notes can be made about the possible hybrids. The upshot can be although you did the right thing and passed on your concerns, the fish are sold off as what ever they look the most like to the shop staff. I know myself my two mystery corydora where originally sold to me as Julii. because as we know all spotty corydoras are julii (tongue in cheek with that one
. ) My point is it is not always the breeders/ sellers/ buyers fault if something sneaks through the cracks even if all care was taken to ensure that the original message was " Caution possible hybrid" .
Here is another example once again using finches as an example but not necessarily hybrids.
Gouldian Finches are quite endangered in the wild, but quite common in the bird trade. So common in fact that now its easier to find mutations than nice original wild stock, (personally I prefer the stunning vibrant wild stock). So one of the ways people wanted to try and preserve the Gouldian species in the wild was to release fully vet checked aviary bred birds. The call went out for contributions from breeders for a large number of wild type Gouldian Finches for this future wild colony. Many of the birds had to be rejected for the program because of so much mutation in feather colour. Keep in mind too many colour variations are recessive and not always visible to the naked eye.
And lastly another example.
Years ago it was feared that a particular breed of Rainbow fish from Fraser Island had gone extinct from its natural lake. A man who had happened to collect some many years previously and never mixed them with other species of Rainbow fish was able to supply his pure fish to National Parks and Wildlife to use for restocking the lake. This would not have been possible if he had mixed his rainbows at some point as rainbow fish readily hybridise.
As I am sure you are aware there are many cichlid hybrids getting about from people having mixed schools and it is getting incredibly hard to accurately identify some of the crosses. The crossing not only influences colouration, but also eventual size of the fish and even character. This is true also of dogs. True in any breed you will have timid dogs, active dogs lazy dogs, glutton dogs but the vast majority of dogs in a particular breed will show certain predictable characteristics. E.g Kelpie generally short to mid length hair roughly a certain height, active and have strong herding drive, body generally remains slim.
Mix this with say a labradour which are well known for being food vacumme cleaners on legs and are retreivers not herders so the two traits don't necessarily gel together well. Least of all if the potential buyer is looking for a dog that is content with a casual stroll around the block once a day, over a hyperactive dog that NEEDs to work to burn off its energy and can turn savage and destructive when not given the chance to use their ample brains.Or in relation to cichlid species a more mellow cichlid like a serverum crossed with a more feisty Jag or Oscar.