Which Corydoras?

[Thursty]

It's kind of like Corydoras sychri but wrong location.
Caught in the Itaya river at Iquitos Peru.

[Karsten S.]

Hi,

this should be C. acutus.

Cheers,

[rmc]

Karsten do you know why they are so Green? My wild caught C. acutus came in like this but it faded with time - it looked so cool which I could make it come back!

Cheers,

Rob

[Thursty]

Thanks Karsten.

As far as the green, every catfish I saw being caught in the Itaya that day had that green sheen to it. At first I thought it had something to do with what they were eating but then somebody suggested to me that it might be a commensal organism such as what colors gold tetras. I don't know if anyone knows for sure.

[rmc]

Thank you Thursty! Very cool look to those fish, I would have loved to see what else you pulled out of the Itaya! Did you go on an organized collecting trip?

As far as the iridescent green color I find this interesting as to what causes it. I have heard of both diet and an organism causing a different color, but I wonder if it is just being outside??? I pulled 4 Brochis splendens out of my tub pond this summer when it developed a crack and 2 of them were what I would call "green laser" green all over their body. After a few hours inside they were right back to their standard bronze color with hints of the green, but nowhere near the same. I would love to try this with my C.acutus, but first I need to get them to breed so that I have enough of them to safely justify "trying some outside" in the unpredictable Wisconsin summer.

Cheers,

Rob

[Karsten S.]

Hi,

well, I think with Brochis this could be something different as you can also see this green in the aquarium sometimes.
But with corys this will always disappear very fast.

Two years ago I was also fishing in Peru among others also at Rio Itaya.
My experience from there is that this green metallic sheen only shows in white water conditions.
In some absolutely muddy water we caught C. arcuatus which looked first like Brochis sp. (only wrt. colour), the same with C. leucomelas.
But within minutes after catching them (no water change!) the stripe / the dorsal blotch appeared...

In Colombia I caught some C. cf. arcuatus in rather clear water and even in the creek itself they didn't show any green sheen.
In Rio Itaya (we were 2 days upstream from Itaya bridge) with medium clear black water the green sheen of the corys caught (C 96, C 53, C. atropersonatus) was rather faint and gone within seconds.

I don't think that it's related to food or water conditions, then this effect should stay longer.
I rather think that this is due to light conditions.

I don't know if you can find C. sychri in Rio Itaya (wouldn't surprise me) but as mentioned there is a cory (C 53) that they locally call C. sychri "trompa larga" but this is lacking the black dorsal.

Cheers,

[rmc]

Thank you Karsten!