Questiondo black eyed Mollies have to have a big tank?
AnswerHi Kasey
Depending on the type of molly(black eye is a color variation, I'm talking if it's a ballon, lyre tail, etc.)they can grow to about 2-3 inches. So, you could safely keep about 3-5 in a 10 gallon tank. Obviously the larger the tank the better. They are an active fish, I wouldn't recommend anything less then a 10 gallon. And, then there's also the "fry factor"....females will have lots of fry/babies, and very quickly overrun a tank.
Good luck!
Christy