I’ve had my fish for 3 weeks. They are all mollies, with a total of 4 in a 10 gal tank. The water is tested regularly to ensure they have a safe environment as I want them to thrive and be healthy. There is also a heater which keeps the water between 78-80 degrees Fahrenheit, (it’s a preset heater). I feed them fish flakes as directed by the pet store (should I feed them something else)? There is no aggression that I have noticed in the tank, and if any just a very mild amount (which I thought was playing) Just two days ago I noticed a large white spot on one of the black mollies and have noticed it hanging around the heater a lot more than normal and venturing through the decor less. It still eats appropriately but then has been returning to the heater area where there are some artificial plans where it hangs out. It doesn’t appear to be ick as it is just one large spot near the fin on the side of the fish. And I haven’t been able to find anything online that looks similar on mollies or otherwise. The other fish still act and appear 100% healthy. The filter has just been changed this week as the old one was gross. I also have vacuumed the gravel and changed the water during the time I have had them. They acclimated well to the tank initially and other than this spot have never showed any signs of distress or sickness.
