They will get to 4 inches long, you can keep 1 of them in a 10 tank, water temps need to be between 71.6-77 F, they will live up to 15 years, water in tank should be no deeper then 12 inches if it's any deeper they will not be able to get to the top to breath, do not use small gravel in the tank as they can accidentally eat it, should have hiding places made of rocks , wood, and flower pots make sure decorations will not be able to fall on them, have a secure lid on the tank as they can fit through the tiniest of holes, gentle filtration should be used as too strong a filter can make water vibrations which they are sensitive too and can stress them, they will eat fish food and live foods such as blood worms, small fish, earth worms, crickets and feed 3-4 times a week.