I have 3 male Guppies. Had them for few weeks now. Few days ago I noticed two of them got really big bellies and one started hanging out in the corner at the top of the tank. Other 2 no other symptoms. I withheld food for 3 days and yesterday I placed all 3 Guppies in QT tank (used a lot of tank water) and added some aquarium salt. There's a sponge filter and a heater set to 80. The QT tank is not cycled but parameters from API test are Nitrite 0ppm, Ammonia 0ppm, Nitrites between 0 and 5.0ppm, PH 7.6ppm (I dont have a test for the parameters). I tried feeding them peas this morning they didn't touch it, tried baby brine shrimp I think they got a few bites in but now the other two guppies are just laying at the bottom corner and the third one still at the top kind of struggling. What else can I do for them?