About a week ago I added 4 male platies to my 29 gallon community tank. It is a planted, fully cycled tank that also has 9 neon tetras and 6 panda cories. All appears to be well in the tank except for 2 of my platies. One platy appears to be bloated, and I asked for opinions online to see if it was in fact female, but his analfin is pretty clearly male. However, this fish is behaving perfectly normal. My other platy has been rather lethargic (he is the one I am worried about). He has been staying near the surface or on the bottom, his fins are “clamped” (close to his body, and his tail is very narrow, which is unlike most platies) and often his lower half starts to angle down until he corrects it and swims away. He has no problem swimming, when another fish pokes at him he rushes away. But these symptoms reappear when there is no stimulus (Update: another platy appears to be doing this). I don’t want to lose him, so I may be overreacting a bit, but if anyone has any idea if this could be something bad, I would appreciate advice. I have heard that cories are most sensitive to changes in water parameters, and they are acting vibrant and normal. Should I isolate my “sick” platy? Should I medicate him, add slime coat, or just watch and see what happens? Is it a swim bladder problem or something that is just him or a problem in my whole tank? The temperature is 79-80 degrees F, I can get my water tested for parameters if it would be helpful, especially if this sounds like a related issue. I would appreciate any help or advice. Thank you in advance!