I've got a 10 Gallon tank. I'd like to get Ballon Mollies, so I'm wondering: (1) How many should I keep in my tank; and (2) Would it be alright just having one type of fish in my tank?
You would be best to keep your number lower than higher due to that fact that babies will be sure to happen..
I would keep no more that 3 ( to start ) one male and 2 females
Keeping one breed of fish in a tank poses no problems what-so-ever so don't worry...
another reason for keeping low numbers during the starting of a tank project is you may want to add one or 2 of something else in the future and it si nice to have the need room instead of over crowding..