I fairly new to fish keeping. I haven't lost any fish til now. I have had 10 tiger barbs for aleast a month and 2 of them seem to be alot smaller then the other. They both often would not swim with the shoal and just stay at the top of the tank by plants or the filter. We 1 of those 2 died i guessing the other might die to but i think he did actually eat this morning. What do i need to do, is it fine to just wait and see or do i need to treat the tank? I don't have anything to test the water except the ph tester and it seems good about 7.4. I just did a water change the other day so i would think all my other levels r ok.