Just the other day I had to get my baby a new tank because graceful me decided to drop the old one. Lil Sano was NOT in there at the time thank God. So I was forced to run and buy a new tank. This tank came with a Tetra Whisper internal filter/air pump. this filter has a mechanical filter and a chemical filter all in one. At first he seemed to just be exploring his new tank. After a while, I noticed he would not hold still at all. He was darting at things like crazy. I took the filter out and he calmed down so much. Now that I know it was stressing him, should I try to ease it back in? If so, how? His last tank was actually a bowl with just a heater so I don't have a different filter for him.