Male Betta Sick

Question
Thank you for your reply.  i have noticed that Oscar is acting different since I put him in his new aquarium with the air filter and the constant bubbles going.  He hasn't eaten and seems to be hiding alot.  I will take it out.  I wanted to know if I should get a water heater and what you would recommend for a 2 gal tank.  The temperature has risen to 74 degrees in his new tank, but I'm afraid that it won't be consistant because the temperature changes so drastically during the night and it gets very, very cold. Please let me know what you think.  Thanks again for your help!
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The text above is a follow-up to ...

-----Question-----
I have more questions about my Betta, Oscar.  I just changed his 1 gal bowl to a 2 gal aquarium today.  The temperature is at 74 degrees and it has an air filter system.  Do Bettas prefer calm waters?  The air filter blows constant bubbles, will my Betta be able to build his little bubble nest at the top?

Thank you!
-----Answer-----
Hi Sheila,
That's really good that you moved him into a larger aquarium.  Temperature in ok but he would love for it to be a little higher.  You are right about bettas liking calmer waters.  I have had bettas become really shy and not want to eat when the water was making too many ripples in the tank.  They would hide and act really different than they would when the water was much calmer.  They would also seem to want to build a bubble nest when the water was calmer and they also liked having some type of floating plant or even a leaf floating that I would remove from a really soft aquarium fake plant. Try more calming water and a floating plant and see what happens.
Hope this helps,
Karen

Answer
Hi Sheila,
There are really small filters if you want to filter his water but you would have to make sure that they don't produce too much current or either block some of the current with a plant---that has worked for me.  As for the heater there should be a really small heater, possibly one for around 2-5 gallon aquariums. Be sure to really check the temperature regularly with a thermometer just  in case the heater doesn't maintain the correct temperature.  I had a heater for a much larger tank constantly overheat the tank and that is really not good. Since that is a small tank keep an eye on it just in case.
Best of luck!
Karen