Hello, I’m wondering if anyone can help me figure out what is wrong with my male platy. I got a total of four platy and two balloon bellied mollies and I put them in my 25 gallon tank. Everything was going well until three platies began bullying the one smaller platy, who soon died. Then one female platy gave birth (she was pregnant when I got her) and soon died a few days later. I was very concerned since this obviously should not be happening, so I got my water tested and everything was normal. I continued my weekly water changes and my fish were doing very well. However, it’s been and a couple months since then and my last male platy is acting very oddly. He is staying at the bottom, not really eating, and breathing semi-heavily. So in response, I slightly lowered the temperature to about 75 and changed some more water (each time I change water I use quick start). Lastly, his stomach seems to be heavier on one side than the other- yes I know it’s weird but look in the pictures. This seems to kind of be like how the others died as well. All of my fish are doing very well, so I'm not entirely sure if it’s something wrong with my tank. Thank you for all of your help!