Cant find correct info on this disease please help

[myunluckyfishies]

I have been looking through the disease websites listed and a few others but have yet to find the correct disease to my problem. Two fish died today and that makes me worry about the rest as one of them had zero signs of disease but the other one was ready to die, loss of apatite. The disease is making my Mollies unable to swim correctly. their back fins are sometimes lopsided but not very often, they are however forcefully using the plants and ornamentation to stay still as they can no longer fight the current on their own. They do come up to eat though and then go back down to their spots. one got better for a few days and see,s to be doing fine now, just hides whenever i come near the tank now.

This is however not affecting any of the other fish in the same way. The guppies,danios, platies in the tank can all swim fine. they do sit at the bottom most of the day though, I blame the very drastic temperature changes in Texas right now, 50 one day 90s the next, tank is going crazy in temperature no matter what I try. Heater cant keep up I guess.

According to the symptoms it is NOT swim bladder disease.

Tank
25 gallon, two months (almost 3), 3 danios, 3 platies, 4 guppies, 2 mollies (1 lyretail) both diseased.
Temperature 77 Degrees
NO3 >20
NO2 >0.5
GH >25 (Hardness)
Chlorine 0
KH <300
pH <8.4
Ammonia >0.2