Dark coloured Adolfoi?

[danceswithfishes]

Hello All, I'm new here. I've been keeping tropical fish for about 2 years.
Anyway, I bought a group of c.Adolfoi online. I received them yesterday. I noticed a darker one, which the seller assured me was different because he was stressed and miffed by the journey, and that his colours would settle. The behaviour was normal.
That was yesterday. Today the cory looks just as dark. Lively, and eating, but still different.
Is it really a stressed Adolfoi, or some hybrid? I tooked pics of the dark one with the rest of the Adolfoi that were in the group.

[Jools]

Looks a bit like

Corydoras(ln9) duplicareus

.

Jools

[danceswithfishes]

Looks a bit like

Corydoras(ln9) duplicareus

.

Jools

I'm going to be super sad if that is the case. The seller came greatly recommended.

[Shane]

Many shipments contain contaminants. Most of us consider them lucky finds. These two spp come from the same river and can be very difficult to tell apart, so I would not be too hard on the seller.
-Shane

[danceswithfishes]

Many shipments contain contaminants. Most of us consider them lucky finds. These two spp come from the same river and can be very difficult to tell apart, so I would not be too hard on the seller.
-Shane

What two especies are these, then? Adolfoi, and....? If you know what the other fish, I'd be grateful. I could go back to the seller with some information.

[bekateen]

Corydoras duplicareus is the similar species. To tell them apart, look at the pectoral fin spines. If they are serrated, you have

Corydoras(ln9) duplicareus

. If they are smooth on their edge, then you have

Corydoras(ln9) adolfoi

.

Here's an example of what to look for:

Cheers, Eric
https://youtu.be/19wS05niin8

[danceswithfishes]

Corydoras duplicareus is the similar species. To tell them apart, look at the pectoral fin spines. If they are serrated, you have

Corydoras(ln9) duplicareus

. If they are smooth on their edge, then you have

Corydoras(ln9) adolfoi

.

Here's an example of what to look for:

Cheers, Eric
https://youtu.be/19wS05niin8

This video is very useful, thank you. I'm straining to see. Maybe your eyesight is better than mine?
I uploaded a close up video.

https://youtube.com/shorts/h9sddPdim-s

[bekateen]

Hi danceswithfishes,

Unfortunately your photos and video do not show the pectoral fin spines well enough to make any judgement. The best way to see the spines is to capture the fish, one fish at a time, and place them in a small transparent (or at least translucent) container in shallow tankwater (just enough to cover the fish). Then if you don't use the flashlight method I used before, then hold the container in the air so that roomlight is visible under the fish. Then you "might" be able to see the serrations with the naked eye. However, I'll caution you that the serrations can be pretty fine (as you can see in my video). Therefore it might be a challenge to see them even in this container.

I used the zoom function on my phone to be able to magnify the videos of the spines when viewed from above.

Good luck,
Eric

[Jools]

You can see them in the heavily edited images from Eric's super video - thumbnails below. However, as a ready reckoner, the thickness of the black line along the back tends to be a good visual key between the two spp.

Jools