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Hi everyone,

A while ago I bought a group of 8 Corydoras schwartzi. I started with 6 and got 2 more from a different store (same supplier) a few weeks later. One of them looks a bit different: he has a black stripe/spot at this dorsal fin.



Some picture of the rest of the group:






Is this a different species or have schwartzi's variable markings? If it is a different species, could it be C. surinamensis?

Thanks! You're help is very much appreciated!

Marlonneke

Doesn't look like schwartzi to me. You may be right that your unique specimen is . Surinamensis has the dark band on the first dorsal rays like your fish. But if yours is surinamensis, that begs the question as to how it got mixed in with the other fish (assuming they are schwartzi, but see below) because the catch locations would not be close. But maybe they share an export site? I don't know, but I wouldn't think so.

In fact, I wonder about all of your fish being . I say this because the dorsal spine on all but one of yours (visible in photos) is dark grey or black; when I think of the schwartzi, I see the dorsal spine as being transparent/hyaline (like one of your photographed fish) or even white/cream colored. That said, there have been recent conversations at CorydorasWorld about schwartzi, in which the key feature is visible by viewing the ventral body surface, looking for plates. Maybe the color of the dorsal spine is a variable trait in schwartzi and can range from cream/white to hyaline to slightly pigmented grey. I don't know how much variation is expected within schwartzi - hopefully someone else with more experience can help.

Cheers, Eric

Hi Eric,

Thanks! I guess without more info on the catch location, it will be very difficult to tell what they are. In the Cat-eLog there is a comment with the surinamensis "Mistakenly sold as Schwartzi", so it happened before.

My biggest concern is that if they accidently start breeding, there are no other fish in the tank that will eat the fry. And I'm not planning on creating any hybrids, so that's something I need to think about, even if they are not very likely to breed (that seems to be a trigger here, because if I don't necessarily want them to breed they do, and if I want them to breed, they don't ).

Hi,

bekateen wrote: 15 Mar 2017, 19:39You may be right that your unique specimen is

Corydoras surinamensis

. Surinamensis has the dark band on the first dorsal rays like your fish.

this is for sure no C. surinamensis. As far as I know there has never been any commercial export of C. surinamensis, it's endemic to upper Coppename river in Suriname. C. schwartzi and C. surinamensis don't share export sites.
If someone writes about a C. surinamensis "Mistakenly sold as Schwartzi" than this ID is for sure wrong.

This species also does not have such a thin dark band on the dorsal fin, it's rather a big dark blotch below the dorsal fin which can extend into the dorsal fin and usually covers than more just the first ray in that case.

Cheers,

Ok, no C. surinamensis then. But what do you think, one species or different species?

Hello Marlonneke,

difficult question. Beside the black stripe in the dorsal fin I don't see any relevant difference.
C. schwartzi seems to be quite variable but as you basically never get any detailed information about the exact catching location of corys that are imported in such huge quantities it's difficult to say if these are not in fact several different species / forms / catching locations...

I assume that this cory is just from a different catching location or a single specimen with a slightly abnormal pattern rather than a different species.

Cheers,