[Aquamarina]

Many thanks for the input.

The chemical I was advised to use was Ruby Reef "Hydroplex-- for treatment of bacterial and parasitic infections". I followed the instructions for amounts to be added to the initial bath and to the Q. tank.

I bought 5 fish because I was told that introducing just one or two to the main tank would cause stress to the new fish. Two Tangs were purchased as there are 4 already in the main tank and one of those is constantly being driven into a cave by another Tang--the new 2 were to help ease the bullying. Other fish in the main tank include a triggerfish, 3 damsels, a wrasse,and some large clownfish, which all seem to be quite territorial and dive-bombed the cowfish for the first couple of days. As well, there is a butterfly, 2 small clowns, a PJ cardinalfish and a couple of stars.

One factor I didn't mention is that there was a rock placed in the Q. tank by the previous owner and I left it there. There was some suspicion the rock harboured some sort of toxin. However, exactly the same type of rock is what has been used extensively in the main tank, so I don't feel that the rock is an issue.

Looking forward to hearing any more ideas on the probable cause of death. How many and what sort of fish would you suggest I get, when I get up the courage to go shopping again?