HElP fish down...picture...RIP

I noticed one of my chiclids (Pseudotropheus demasoni) stopped eating and became less aggressive, all the other fish avoided him, and he started to just kinda floated not really swim. So i figured something was wrong and took him out of the tank and put him in a 10 gallon one with nothing else in it. Within 1 day he started to get large greyish white spots on his sides. He died within the next day...RIP

A few days later i saw another one of my chiclids (Sciaenochromis ahli, i think) start acting the same way the other one was. So I took him out put him in the same 10 gallon tank as the other one. Same thing happened the next day but this time he had the greyish white spot on his chest and it was kida fuzzy looking. He passed moments ago... RIP

I would like to know what it is if u know so if another one of my chiclids get sick i can treat it.

I have a 55 gallon tank.
7 Chiclids in it. they have been in for about 2-3 weeks
idk the PH level and all the other levels
TEMP is 70-72...i know bit cold but i dont have a heater yet

the eyes are fine its just glare...