help for betta

Question
Hi.
I have a betta. He is about a year and a half old.
He has always been a good eater. I used to feed him bloodworms because thats all he would eat. Recently he has stopped eating. Starting being lifeless. And started loosing color. I have read lots of question and answers with similar problems and lots involve temperature. Its hard for me to believe that that is the problem because he was fine all winter when it was very cold and he was fine last summer when the air conditioning was on. Tonight I fed him some new pellet food and he ate one. But not the other two. I also put some antibiotic medicine I bought in his bowl. It says its for fin rot and all kinds of betta diseases. I'm really afraid he might be dying since he is getting old. And I'm just sick about it. Please help.
Thanks.
Cloe

Answer
Chloe,
You need to make sure he is getting all the nutrients he needs. While they certainly love bloodworms, they don't contain all the essentials he needs in order to live, so it's important to have a base diet of betta pellets and use bloodworms as occasional treats only.
Make sure you are changing out his water often enough. If he is in anything under a gallon, I recommend changing out his water completely twice a week, and upgrading to a two gallon or larger as soon as possible. If he is in a one gallon, change out his water once a week, and so forth.
Buying a water test kit is a great idea for any fish keeper because it will let you know the conditions of your water at all times and whether you need to do a water change soon. You can buy these at most pet stores - you'll want to get a test for ammonia, as well as nitrites and nitrates.
Also, you should get a thermometer so you actually know the temperature of his water. They are tropical fish and need warmer water than what your house temperature may be (between 75-85 degrees F, around 80 being the best).
If you notice his water is too cold (below 75) than you'll need to buy him a small tank heater. I usually see them at Petco, they are the mini tank heaters (7.5 watt) and normally cost around twelve dollars.
Best of luck to you, have a good one.