Unidentified heptapterid species

[wrasse]

This cat is a mini-masterpiece! It has the outline of a brachyplatystoma but is only 3" long+ that huge tail. I think it maybe nearly fully grown.

[Jools]

It's a fantastic catfish - catfish of the year? Certainly the month...

Is it from the Ucayali drainage?

Has the name Imparfinis cf. cochabambae been mentioned?

Cheers,

Jools

[wrasse]

Thanks Jools. At this point all I know is that it's from Peru.

Imparfinis has not been mentioned, til now.

This specimen is now fully quarantined and settled and feeding well.

[Jools]

It's very close to a (probably) undescribed species from the Ucayali that I saw years ago - probably still on the 'net as pre Facebook era. I would also like to find out more about Imparfinis longicaudus (Boulenger, 1887). There appears to be a few fish in that genus that at least look like your fish. It is odd also to note how many heptapterids have no pigment around the gills. I suspect also that the fish is only black under aquarium conditions being paler in natural whitewaters.

Long caudal fins don't tend to do well in preserved specimens, so this cool feature could be hard to use for ID against pickled fish.

Jools

[wrasse]

But why then, would it not exhibit black colouration in its natural habitat?

This fish's colour faded a little when it was netted, but was black again very soon after being released.

[Jools]

In whitewater, fishes tend to be pale. In clearwater, many species, especially those that live across both types of water, tend to show more pigment and/or colour. I don't know why but one could guess it's to make them harder to see.

Jools

[wrasse]

All the Imparfanis species pictured in the Catelog fit your description of whitewater fish colouration.

I don't think this fish is the same. It's well-pigmented with a black-purple body and a pale orange tail... presumably for a reason. Maybe clearwater, deep water... And for display?

[wrasse]

Also, I have not seen this fish attempt to bury itself in the sand.

[Jools]

There is a lot more to Imparfinis than the pics I've managed to gather into the Cat-eLog. Have a read of this. There's a load of described species your fish might be and a lot of work in discounting them...

Jools