Thanks Suemack and Lordmoose for the advise. I had done pretty much what you said moose about using half dose of the whitespot treatment as I,ve got a cory in there. I don,t want to put any salt for that reason. I did a small waterchange when I treated and I,ll do another one when I retreat tommorrow. (the bottle says to retreat after 3 days). The fish have stopped flashing so much but there is a bit of scale missing from one of the silver sharks and it looks like brown flesh is exposed. Has anyone ever treated for whitespot before, would you know if the scales might fall off or something when the parasite dies? I think the redness on the side of the tiger barbs is going away slowly. I tested the water again last night and to my supprise ammonia and nitrites were negative.(0) Nitrates are 5ppm.There is a bit of algae in the tank now and the glass is getting quite brown but the actuall water looks and smells fine. Do you think the algae might be a problem? Watching the fish last night they all seemed to be acting normal again so hopefully this is the end of it. Will keep you posted. Oh, somebody mentioned PH down is a bad thing. I used PH down over a couple of weeks, do you think this might have hurt the fish?