Keeping water warm and comfortable

Question
I have purchased a male betta blue and two African dwarf frogs.  I know to keep the water room temperature.  I have them at work in small aquariums.  But the temperature of the work environment may be a little cool.  I have a small lamp over the fish aquarium and the frogs in a separate aquarium.  The fish prefers to hover under the lamp.  Is there a possibility of having these small aquariums put into a larger aquarium with warm water or heater in the larger one?  Even though I found that the frogs are healthier in warmer temps I found that even the slightest temp change will cause them to go eratic.  I want to be sure to do the right thing and create only a gradual change in temp and a comfortable one.  Suggestions please?

Answer
Hi Steve;

They would all be very comfortable in a five or ten gallon tank together. Get a heater for it and they will be all set. A five gallon typically needs a 25 watt. A ten gallon needs a 50 watt. This should maintain a suitable temperature without the ups and downs they have been experiencing.

Frogs get more hyper in warm water because their metabolism speeds up. They sometimes dart around like maniacs to escape from possible predators when there is movement too. It's really their only defense mechanism. They sure are cute little fellas!

At Your Service;
Chris Robbins