Mollies are hardy fish, however I do not recommend a Black Molly for a starter fish. I would suggest getting the aquarium set up and the biological filter established before purchasing any. Hybrid Mollies are more susceptible to disease. The extra stress from high toxin levels would only increase the chance of the fish getting sick. The Silver Molly is a better choice for starting a tank. Or you can use NutraFin Cycle Biological Aquarium Supplement
Mollies are schooling fish and do best with 3 or more of the same kind. However with most live bearing fish the males may have little battles for dominancy. The weaker male will then suffer. The best solution to this is to have two or three females to every male. I would suggest that a school of eight mollies should only have 2 males max.
There are many different opinions on Mollies and aquarium salt. Do they need salt? Do they like brackish water? From my personal experience with Black Mollies I have seen them healthier and livelier when I have added salt to the water. I add 1 tsp every time I change out 10% of the water in my 20 Gal tank. I recommend using API Aquarium Salt
The Black Molly is easy to keep and easy to breed. They will eat all kinds of food including flakes and algae. I suggest TetraAlgae Vegetable Enhanced Crisps
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