Freshwater Aquarium/20gal stocking



We have a new 20 gallon high tank for freshwater fish.  I was wondering if you could give a few stocking idea options as I've seen a lot of different people say different things. Preferably the most peaceful fish that will get along, and if there are any male to female ratios to be aware of, please let us know that as well.  


Hi Ginger

I have a 20 gallon high tank with a German Blue Ram, Dwarf Blue Gourami, 3 Black Mollies and a red Betta. The Betta does not bother any of the others and it is a very peaceful tank. I used a dark brown natural substrate with live plants and it is one of my more beautiful tanks to be as small as it is. This is just one suggestion. In this tank, all 3 Mollies are female. With most fish, especially Mollies and other livebearers, it is a good idea to have more females than males. I use the 2:1 ratio - 2 females for every male.

In a 20 gallon you're limited to quantity so I would avoid schooling fish that require groups of 5 or more. There are many community tanks you could do with a 20 gallon, just keep smaller fish that will be 3 inches or less as adults. Rather than list all of these here, I provided a link below with several community tank suggestions.

The only other advice I can give is to avoid barbs and most tetras as these can be fin nippers.

Hope this helps you, good luck!


Freshwater Aquarium

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Richard Hight


I own and maintain several freshwater aquariums from 2 to 180 gallon. I can answer most questions about freshwater aquariums, including setup, cycling, maintenance, compatible tank mates, feeding. Moving? I've moved fish both across town and across the country and can help you get your little aquatic friends to their new home safely. I know and have experience with most freshwater community fish, South American Cichlids and African Cichlids. I don't answer questions about Goldfish or keeping Goldfish with Tropical Fish. I also don't answer questions about keeping crustaceans (shrimp, snails, crabs etc) with Tropical Fish, nor questions about saltwater fish or aquariums. I'm not available to answer questions on weekends, this is when I do maintenance on my own tanks.


Many years of personal experience with community tank fish, semi-aggressive fish (Barbs, Tetras, etc), Angels, South American Cichlids and African Cichlids.

HSG 2010-2011 prof

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