I have 8 fry mollies and 4 guppys. They were in two different nets in the big tank. I had a gallon tank that had my youngest daughters fish in it so i put big fish in main tank and refilled the little tank with main tank water and put babies in there with an air stone. Should this be ok or should i put a heater in it too? I will be moving them to a 10 galloon once I get it cycled.