That really depends on how you want to set it up. Minimum, I'd go with a 20 gallon long. With some cover (fake plants or real). This way you can have some adults and still have some room for the babies. Or you could set up another tank say 5-10 gals. for the babies to grow in. I prefer the first idea because I dont like moving the babies. The main reason is it stresses them out. Another is because I don't like to go hunting for them in a tank with heavy cover.