Multiple sick fish

Question
Hi Elizabeth,
I have some problems with my fish. I have had a tropical fish tank for about 4 months. Everything started off fine as I built and added fish. However I added 2x mollies from a shop that I thought was a bit suspect and about 10 days after that I noticed white fungus?? on the tail fin of one of the mollies and on a number of neon tetra's. Both mollies have since died in the past week.

Then Friday one of the Dewarf Gourami's got a bloted stomick in the morning and died that night. It now appears that 2 of the Balck Widow tetra's have bloted stunicks.

I have tested the water and everything looks fine apart from a slightly elevated PH. I am sure I have somthing in the water killing these fish but are unsure of what. I have used both Wunder Tonic and MelaFix to treat the fish, but this has not helped so far.

Any ideas?

Answer
Bloated stomachs are a sign of internal parasites, I find that by the time they start to visibly bloated it's too late to treat (depending on the size of the fish).  Mollies tend to get fungus if you don't add aquarium salt to your water.  There are mixed opinions on whether or not you have to add it or not.  You can still try treating with a general parasite killer, but you have to be careful when treating tetras, so read the directions before you add anything.