CPD fry’s in a non heated and non filtered tank help

I have moved my cpd fry’s into a small tank that has no heater or filter. Will they survive in there if it gets cold? I will put a thermostat in the small tank ever 3 hours in the morning. So it is heat sometimes. However overnight the tank will not be heated that’s the problem but I will leave the heater for about 10 minutes in the small tank before I go to sleep then move the heater to the big tank. Will my cpd fry’s survive or not please help. What are the maximum temperatures they can survive and what is the minimum temperature they can survive in. :cry: should i put them in the cellear it is quite warm in there?