I think I am going to start a sorority in my 10 gallon. I have a heater, decorations, and gravel. Ive been debating whether or not to get a filter. Is it recommended, and if so which would you recommend? I already have 2 females, Abigill and Rosie, so Im guna pick out some more soon. Im probaly going to go with either 4 or 5. But first I want to get the tank ready. So filter or no filter?