I know platies can get a decent size but I really do not know what else to put in this tank. I am already going to divide my 10 gallon and put two betta's in it. I could divide this tank and do the same but I rather have different fish in each tank. Only other thing I would be willing to get is a fancy goldfish but he/she would out grown that tank easily within the first year and I can't up grade the tank anytime soon. My boyfriend seemed to be interested in a fresh water puffer but they just seem like they would be a lot of work.