New thrd ..HELP plz . sick fish

[voodude]

Yesterday my sailfin (2 wks in tank) just kinda hung out in the water stream from the pwrhds and didn't spook when I went by the tank ... this morning, it was doing the same and when I fed, it didn't hide .. tried flake, then some pellets and finally I waited until it was looking and dumped some brine shrimp (which it likes) and swam right thru without eating. Few minutes later, it was sitting on the bottom leaning against a gorgonian and kinda huffin-puffin. Now back up in the water stream. All readings last night were normal/zero except nitrates, which alwasy run 30-40 (still tryin to figure that one out (something other than overfeeding and ditritus)). just moved a trigger out of the tank before getting the sailfin. I know somethin is not right, but do not know what to do ..