pyramid butterflyfish?

[Aquattro]

Update - of the 5 of these, I've lost 4. 3 were recent imports, and after moving to the new tank a week into having them, one a day for 3 days died. Tonight, one of my established ones died, it's tail was rotting off and it started rolling, I pulled it and put it down. The 5th is doing great, and shows no sign of weakening, so my assessment of these fish is "if" they settle in, they're great and easy to keep. Big "IF"...

All other fish in the tank are doing great, so I don't have reason to think it's new tank related.