New to the tropical fish side of things and still getting to grips with it,
bought a tank before xmas and got everything i needed to start it up. gave it about 3 weeks before putting fish in and all was good. got a few fish in there over the past few weeks and then i bought some Ramms from our local pets @ home. atr the time i had a red tail shark and it wasnt happy with the 2 new fish so i got rid of the shark (it was picking on em and injured one of the fish) this caused a cotton woll ball to appear on the fishes behind. i went back to the fish shop and they said it sounds like a bactierial infection use this to treat it - Interpet No 8 Anti Fungus and Finrot. i did this and after about a week it dropped off and it was all gravy again. i bought 2 tetras and a panda catfish and within a week the 2 tetras had died. both seemed to get whitespot or something similar and went fluffy once they had died. they went from being fine to dead within hours and within days of each other. put some anti whitespot in and bought a pair of platys last friday and they seemed to be fine, then i noticed this same white spot look on one of em. now during the course of today. i think they are both dead. one is definatly dead and i cant seem to spot the other right now.. during the course of it all my nitrate, nitrite, ammonia, high and low ph levels have all stayed roughly the same,
ammonia being at 0.25
ph 7.0
nitrate 0
nitrite 0
any ideas what is causing this. all the other fish seem to be ok
before i put the ramms in and took the shark out i had about 4 guppys die, but from what i hear they can just be like that.
the yellow barbs and guppys seem to be rubbing themselves on the bottom, on the gravel?
bought a tank before xmas and got everything i needed to start it up. gave it about 3 weeks before putting fish in and all was good. got a few fish in there over the past few weeks and then i bought some Ramms from our local pets @ home. atr the time i had a red tail shark and it wasnt happy with the 2 new fish so i got rid of the shark (it was picking on em and injured one of the fish) this caused a cotton woll ball to appear on the fishes behind. i went back to the fish shop and they said it sounds like a bactierial infection use this to treat it - Interpet No 8 Anti Fungus and Finrot. i did this and after about a week it dropped off and it was all gravy again. i bought 2 tetras and a panda catfish and within a week the 2 tetras had died. both seemed to get whitespot or something similar and went fluffy once they had died. they went from being fine to dead within hours and within days of each other. put some anti whitespot in and bought a pair of platys last friday and they seemed to be fine, then i noticed this same white spot look on one of em. now during the course of today. i think they are both dead. one is definatly dead and i cant seem to spot the other right now.. during the course of it all my nitrate, nitrite, ammonia, high and low ph levels have all stayed roughly the same,
ammonia being at 0.25
ph 7.0
nitrate 0
nitrite 0
any ideas what is causing this. all the other fish seem to be ok
before i put the ramms in and took the shark out i had about 4 guppys die, but from what i hear they can just be like that.
the yellow barbs and guppys seem to be rubbing themselves on the bottom, on the gravel?
Add enough Whitespot to treat any and all replacement water you add. You'll see why I add this here, when you read the links to the articles below....
How long have you had the fish in now roughly and what test kit are you using? It sounds like you have had fish in for a while, so you'd expect to be seeing some NitrIte by now
What are the chances of returning some fish? Guppies and Rams are hard enough to keep in a mature and well established 6 month old tank, let along one thats cycling, so keeping them will most likely kill them 
Very few shops will accept diseased fish back due to the risk to their own stock, so you may well be forced into a fish-in cycle