Hi I’m new here and a new aquarium owner. I have had a tank up for 5 months. I have 4 Robertsi tetra, 2 Siamese algae eaters. 1 angelfish, and 3 mollys (1 male, 2 female). In the beginning I lost a couple tetras but they seem stable now. But I’ve lost 4 mollys within a week or 2 of getting them. I replaced the first 2 and then replaced them again. I have a 29 gallon tank. My water tests okay with master test kit and test strips.I do weekly 25% water changes and filter pad changes every 2 weeks. The other Mollys seemed fine and then just died. If they did anything unusual it was hiding away for a day or two before they died.I have one right now that appears to be having a swim bladder problem. She can’t swim right and bounces all over. She’s been like this for about 4 days. I didn’t feed them all for 2 days and then tried to feed her peas as was recommended online. I’m not sure if she actually ate any but it looks like maybe. But no improvement yet. My pH is around 7, GH 250 no nitrites low nitrates, low to no ammonia. Heater is at 77.