Right now I have 2 small oscar, 1 small arowana and 1 pleco in my 10g tank. My 2 oscar most of the time are floating on top of the water surface I'm not sure if their in need of an air pump/air stone thingy. Are they gasping for air? Right now I have everything but the air pump in the tank. Im gonna get a 65g tank soon and am going to moved them to that tank. My water seems a bit cloudy the food that I feed my oscars are pellets and sometimes they don't eat it all and some of'em get stuck on the filter. Some of the food they eat are turn to little ones and are now on the bottom of the tank I clean it yesterday but today it came back. Would I stress them out if I change the water alot? every couple of days when the food goes to the bottom. I dont have a testing kit so I cant tell you about the water result thing.