How to slowly heat up the cold water my Bettas in?

[Nicpatmore]

PLEASE HELP!

I was told by the fish store that my Betta could live in an unheated bowl, which he's been in since Saturday when he came home.

I've read up all about him and now know that he needs to be heated!

I have a larger tank and heater ready to go... Here's the problem

The water he's in is 58degrees F (I can't believe he's in it, poor thing)
The thermostat on my heater only goes down to 68degrees

I know I shouldn't change his temp too drastically.

How do I best raise the temp from 58 to 68, given that I can't set the thermostat lower? It takes about 1 hour for the tank water to warm up to 68 and its currently not warm, and he's in the cold bowl.

If I put him in the tank and warm it up over the next hour to 68 degrees will he suffer?

Advice gratefully received

[shellieca]

Congrats on your new Betta & yay to you for doing research. I would remove him from the tank into a container you can float in his tank, do a water change on the tank with the new water being as close to the temp you want as you can get it, make sure you add conditioner, add the heater if you haven't already & turn it on. Float his container in the tank, only leave enough water in the container that he can comfortably swim around, add one tablespoon of the tank water to the container about every 15 minutes for an hour or more then release him. IMO, its no different than when you bring home a new one & want to add him to his new tank. Hope this makes sense, ask more questions if not.

[Crowntails]

Raise it slowly over a whole day period of time. Your gonna need to get a stronger powered heater to raise the temp to 78 degrees where bettas like it best.

[Nicpatmore]

Thanks. That's really helpful. We've started the process and are confident he'll be happy! Our heater goes way above 68, but I think I might leave it around that for a day so he doesn't have a 20degree jump all at once. Then I'll go up 2 per day til I reach 78.