Help! Rummy Nose tattered tail fin & hiding

[catwoman]

Yesterday, I just moved 5 new Rummy Nose from the QT to my 75 gallon tank where there were already 5 healthy Rummy Nose. There are Clown & Yoyo loaches in the tank as well as a host of other healthy fish - danios, red phantom tetras, etc. Today, one of the Rummies has a tattered tail fin and the base of his tail & back 1/4inch of his body is white. The rest of his body is normal color and his nose is even red. He is not schooling with the others but hanging out in a corner. The tank is well established and all water parameters are good with very low nitrates. It doesn't really look like pictures of fin rot and this happened overnight. I am wondering if one of the loaches ripped his tail up? Do they do that? They are constantly pestering all the fish in the tank. Why is his back end white? Is it some other disease that anyone has seen before? I do not have much luck with Rummy Nose. Seem to be very sensitive fish. When one stops schooling and hangs in the corner, it is usually dead within 24 hours. Anything I can do?

 

[impur]

Schooling fish will sometimes pick on the smallest or weakest of the bunch. Its just nature. The white part of the body could be a result of the beating. They may have picked off some of the scales exposing the skin. You might try removing it and trying to nurse it back to health and re-introduce it at a later date.