You need to get a better heater that can heat the tank at the right temp all of the time. I think you could do this on a 10 gallon
1-dwarf gourami
8-neon tetras or 10-green neon tetras
20 or so ghost shrimp
1-dwarf gourami
8-neon tetras or 10-green neon tetras
20 or so ghost shrimp