I had 2 cowfish die before getting one to live.Never had any problems with tank gassing.I even had a black female boxfis die in population and no effects.I think that is over arted and the only fish I would be worried about is a blue boxfish.The cowfish I have now was the size of a twoonie when I got him.Right know he is with his tail maybe 7 inches.He grew fairley quick.The fish I had with him are cling fish , 6 line wrasse, scooter blenny, lawnmower blenny, long nose hawkfish, and a cubicous boxfish.He lives in a 120g but I still think I will need a bigger tank in a year or so.If you have ever been to riverfront the cowfish in the display there is smaller than mine.
