You don't say anything about the equipment you have for your 5 gallon tank - like filter or heater or how long you have had it. You also don't say how long you had the females - they could have already been PG. Anyway, I am wondering why you got a male if you were concerned - you do know about the birds and bees etc. right - Platys and mollies are at about as prolific as guppies. They breed like rabbits. Hopefully they will eat most of their young if you let nature take its course, but that doesn't always happen. You could check thrift stores and Craig's list for tanks - do remember some of those containers are could be reptile containers which make them unreliable to hold water for long periods. Good Luck!