there are a load of new unnamed species in the trade now. I haven't seen these ones before - could be a form of aeneus but probably more likely to be a different species. You could browse through here if you care to: PlanetCatfish.com - The genus Corydoras
Thank you both and esp. Chlidonias for the link, very usefull but at the same time somehow depressing because now I know many of my Corydoras ID's will never been solved ( some many species, so many still unnamed, so many which somehow look simmilar, some without a picture....... ) !
There is another possibility. These fish may be a common species, such as C. aeneus, which have been dyed. This practice has been around for a few years now, although most fishkeepers are disgusted by it. My suspicions were aroused because fluorescent colours like this yellow one are often used. The dye is usually injected, often with fatal consequences, but that wouldn't work with armoured catfish like Corys and wouldn't colour the fins either. But I did an internet search and I find that they can be coloured, probably by raising young fish on food containing dye. For further information see Death by Dyeing.org - Shades of death. I don't think I need to add that responsible aquarists never buy such fishes and I would recommend avoiding any shop which stocks them. Alan
Very unlikely, I believe. First, because the fishes used for dyeing are usually more translucent, usually this it'ss done with Parambassis ranga, Gymnocorymbus ternetzi and Danio rerio, and it's unlikely that somebody uses a Corydoras for that, because colorus would not show as easily as in these species. Second, because colours used in dyeing fishes are phosphorite pink, green, blue... not this natural-looking metallic greenish shine and yellowish that looks like more natural in a Corydoras. And third, because dyed fishes can be seen easily at pet shops and aquarium shops and in home aquarium of somebody, but I never saw one in a public aquarium that is a more serious institution and usually concerned about this problem.
You may be right. But I still think that this colour does not look natural. The website I mentioned previously says that coloured Corydoras have been seen, although I agree that the species you mention are much more often the victims of this practice. I admit that I assumed that Aquazoo Leerdam was linked to an aquarium retailer in some way: because some of fishes in vogelcommando's photos look like dealer's stock and there happens to be a business called Aquazoo in the UK. From visiting the website it seems to be run by a collective as a public aquarium; if this is so I agree that they are unlikely to have dyed fish on show. I am happy to apologise to Aquazoo Leerdam if this is the case. Alan
@ gentle lemur : Aquazoo Leerdam sutainly isn't an aquarium retailer, it's run by a group gf aquarium hobby-ists which are doing - at least IMO a very good iob. It is however of course possible that one of these hobby-ists obtained these fishes from a dealer and then placed them at the Aquazoo. They looked however healthy and somehow I find them looking natural ( and beautifull ! ). Hope someone else do know the exact species and can solve the problem of the ID.
I don't think the fish in this photo are artificially-coloured, but I have seen painted corys on a number of occasions (to NZ they were usually imported from Singapore - I think it may have been made illegal to import artificially-coloured fish now though). They use the albino ones and literally paint them so there are coloured stripes along their bodies, or for a more overall colour they dip them in dye. When I first saw this photo I was reminded of the new species (plural) labelled as gold line, orange laser, Peru orange stripe, etc. I think there are a few different undescribed species in the group but I've only seen photos and they all look different, and because I've only seen them on fish-keeping sites there is a lot of conflicting info.
