I have had my 50 gallon freshwater community tank set up for 3 months. It is fully cycled,
ammonia 0, nitrites 0, and nitrates 10ppm. My fish have been extremely healthy, and the water levels have been great and stable for over a month. I currently have 2 angels, 5 rainbows, 5 mollies, 2 bala sharks and 1 small aquarium frog. As I stated, all fish have been extremely healthy, no bullying, no conflicts, no illnesses for at least over a month. Yesterday I noticed that 2 of the female mollies and my male molly have all been hanging around the surface. I have an air producing filter (good for up to 70 gallon tank), a live plant, and I have a shell that blows huge bubbles, so I doubt oxygen is a problem. I don't see anything else on the fish to indicate illness...any ideas?