I am officially the worst fish keeper ever, this has just been one disaster after another. My tank was started last October and levels have been consistent since December ammonia 0, nitrite 0, nitrate 5. I keep the temp at 80. Last week my 20 gal tank had 3 dal. mollies, 3 platies, 3 guppies and 2 neon tetras. Everything seemed fine until one of the platies (my favorite ) had clamped fins and wasn't very active. There were no signs of ich or any other apparent problem but i turned the water temp up to 86 just in case. About 3 days later that platy died and I did notice one white spot (ich?) on her tail. I did a water change and in an effort to save the rest of the tank I added 1 drop/gal IchStop for 3 days per label with carbon filter out. Well the next morning when both neons were dead I realized they could only handle 1/2 drop per gallon. Everyone else seemed fine, but on day 4 one of the guppies died. Again, no sign of ich or any other problems. I did a 40% water change even though parameters had not changed. Its been about 4 days since that guppy died, temp still at 84, but another platy is clamping fins now and some of the mollies seem to be flashing. Also, Ive noticed 3-4 tiny fry in the tank, really not sure who they came from, but if I had to guess it would be the platy who isn't acting sick. Does anyone have ideas for what I should do or what the problem might be? I've lost 2 whole tanks of fish already, plus replaced a leaking tank - I just want to be able to enjoy them! I feel flake food once a day and there is an air bubbler in the tank in addition to the filter. One more thing to mention, sometimes the fish have long white strings hanging out of what I would assume is their butt. The string is slightly thicker than a strand of hair and anywhere from 1 - 5cm. Sometimes they swim around for hours before its gone. What could this be? Thank you in advance for any help!