Please could anybody offer me some advice with my new tank trauma [I only have a small Bi-Orb]. I had my water tested at an aquatic shop and they told me it was good quality and ready to go, although it had only been set up for 2 weeks. I tried to keep things simple by putting in only 10 guppies [12 days ago] but because of the small volume of water in the tank and the fact that it wasn't fully mature, the water quality has gone haywire. The nitrite levels were sky-high last week, so I started a series of daily water changes of about 20% each time, always replacing with filtered/de-chlorinated tap water. I think I repeated about 4 changes [using Stress Coat and Stress Zyme] but haven't done one since Monday as nitrite readings were still relatively high after each change and I've been worried that I was replacing too much of the original water. I've cut right down on feeding instead and also added some more of the biological filtration rocks [they call it ceramic media] to encourage bacteria growth and I bought a nitrite treatment [sorry can't remember the name] which I've been adding daily [as recommended]. One guppy died yesterday and 2 others are behaving as if sick. I'm sure that 1 has fin rot and 1 think 1 other may have an intestinal worm. Both males seem to have symptoms of 'shimmying' and frequently hover on their own for long periods. The 1 with the worm [I think] also seems to have trouble using his pectoral fins, as their movement seems limited. I know both are in urgent need of attention, but I don't know what to do for the best. I'm worried about adding medication to the tank as I feel that i've mucked about with the water enough already - but obviously, I haven't got the luxury of a mature 'hospital' tank to treat them in. I know I'm only talking about 2 guppies [the rest seem fine] but it's hard to watch them deteriorate without doing anything to help. Should I just concentrate on trying to get the water right and accept that I can't do much to help them - do I have any alternatives? Grateful thanks to anyone who can help