The true Corydoras julii & a new species

The issue of the identification of the species Corydoras julii Steindachner 1906 frequently arises, as the majority (so it would seem) of so-called "julii" cories in the hobby are actually not this species but more likely C. trilineatus. The true julii species occurs in NE Brazil. A new post on CorydorasWorld has photos of wild fish of C. julii along with a new species that Ian Fuller has authenticated as CW 185. Both species were captured in the Rio Granjeiro in the state of Ceara, in NE Brazil.

And before someone mentions it, the tank used for the photography of these fish has a gravel substrate. Hudson Crizanto Goncalves, the member who posted the photos, assured me that these fish are normally in sand substrate tanks.

I had a little book when I was a kid, found in my fishkeeping grandfather's back shed. It said there were 4 species of Corydoras - melanistius, aeneus, paleatus and... julii. So that problem with misidentifications goes all the way back to the 1940s, when that book was published.

Things looked simpler then! I mean, I thought I had seen all four.

Awesome pics Byron. Let's be honest : they look quite different, don't they ?

DoubleDutch said:

Awesome pics Byron. Let's be honest : they look quite different, don't they ?

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They are two different species that happen to occur in the same water course. The second is not the species frequently labelled as julii, just to be certain everyone is on the same page. The "julii" available in stores is another different species not found in this river at all, C. trilineatus. This may have become confused by my posting both sets of photos.

I think I have the one on the left, the true julii. Darn fish practice such good protective coloration I couldn't see them well on black sand, now I can't seen them well on tan sand, helps that they are in the bottom 10 and getting down there to take a picture is quite difficult. and never mind, I looked up the C. trilineatus and I might have those

Alice B said:

I think I have the one on the left, the true julii. Darn fish practice such good protective coloration I couldn't see them well on black sand, now I can't seen them well on tan sand, helps that they are in the bottom 10 and getting down there to take a picture is quite difficult. and never mind, I looked up the C. trilineatus and I might have those

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The spots/pattern on the head is usually the clue. C. julii have circular spots, not connected, whereas C. trilineatus has a reticulated pattern, not distinct dots, and some of the markings are connected like small squiggly lines, making this clear.

I'm going to have to get them into an upper tank where I can see them to find out

Byron said:

They are two different species that happen to occur in the same water course. The second is not the species frequently labelled as julii, just to be certain everyone is on the same page. The "julii" available in stores is another different species not found in this river at all, C. trilineatus. This may have become confused by my posting both sets of photos.

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I mean that the C.julii and C.trilineatus are quite different.

DoubleDutch said:

I mean that the C.julii and C.trilineatus are quite different.

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Yes, I think so too.

Practical test one: Did you pay a very high price for each julii? $50 to $100 and up each? If no, likely trilineatus....

I think they were $5 or $6 apiece.