i recently bought 4 azul about 2-3 inches in size. suddenly one azul start breathing very fast i thought first they are fighting so i feed them more. i usually feed at night only. but in the end it died. now one of them is breathing quite fast again. i observed water is quite cold so i put heater. so far the fish survived but it still breathing quite fast for 3 days and still wont eat. i check water parameters are ok and the other are eating like pigs. so anyone here can help me out??? pls...