i bought a longnose about 2 weeks ago and he was loving the tank when it just had a overhang filter and powerhead. since then i added another powerhead and a skimmer and now the hawkfish is just sitting around the sand and not cruising the rocks like before. hes breathing and still bright colored, he flares his fins when i come close and lets them down. when i feed the fish he seems intrested (looking around and flaring fins) but then does not go for it. i feed them frozen brine shrimp and flakes every so often. all the other fish are cruising around having a good time and the water tests are good. should i be worried?