Hi--I hope someone can help me. My 30 gal.tank was set up in December, I added a few small fish in January. (neons, white clouds). I have gradually added a few fish at a time. At present, I have 1 catfish (1 died this morning), 2 rasboras, 3 white clouds, 3 neons, 1 marble hatchet (1 died this morning) and a male betta. The catfish were both in the tank since December. All the small fish are fine--actually--ALL the fish SEEM fine. They have great color, they are growing, eating well, swimming about the tank--yet--sooner or later-with no warning-I lose another one. I had 2 marble hatchets originally--one died; I had a female betta-she died; a ram cichlid (really upset over that one)--she died. It seems the "original" occupants are the only ones I haven't lost (with the exception now this morning of the catfish). They show no signs of illness, disease--one day they are healthy & happy--next day they are dead. I had my water tested at a fish store--they said "everything is fine" with my water!!! The only thing I notice is a tendency for my PH to be slightly more alkaline . But I was told that would hardly kill off these fish this way. I would like to get this tank with a few more fish, but I don't dare buy any!! (I have gotten them at different locations also--no "WalMart" fish either) Anyone????? (please-ask me any questions you need to know that might give you a clue) Thanks!!