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...