try some live brine shrimp. their available in many fish stores. Their swimming motion can trigger feeding responce in the betta.

Is he warm enough? I had a betta in a one gallon container that wouldnt eat, but it was too cold. After I put him in a regular 10 gallon with a heater, he perked up and eats.

Also bettas REQUIRE some aquarium salt in their water, at least 1 teaspoon per gallon, but up to 3 teaspoons per gallon can be used. Thing is, some other fish you might want to put with the betta in the aquarium cannot handle 3 teaspoons of salt per gallon, so I tend to stick to 1 teaspoon per gallon. Neon tetras (get 8-10), and a couple corries mix well with a Betta.

Betta's do not actually REQUIRE salt. A lot of people experience constipation in their betta fish, and this can be treated with simple plain epsom salt.

The advice of heat is very good though. A betta needs a temperature of 78-80degrees. Also, ensure your ammonia, nitrite, and nitrate readings are good. API liquid master test kit is one of the best. Test strips are very inaccurate and you won't be able to care for you fish properly.

Ammonia and nitrite should both be at 0, and your nitrate should be under 20, but preferably below 10. All three of these are very toxic to fish, and when not kept in proper levels will do a lot of damage to your fish.

I recommend a 50% water change, using a gravel vac to clean all substrate. And the advice of live brine shrimp is good as well.

Best of luck to you.

Bettas are actually pretty hardy fish. You can usually bung em in a tank and they should be fine (as long as you dont go from cold to warm watever too fast ...let them adjust first by letting the bag sit in the water for awhile before you release them). Anyway i have had bettas that wont eat t begin with. One i had to feed one pellet too and wait for it to eat that n then give it another one. It would only eat the pellets if they were sinking and fell right infront of its face. They can be very picky with food. If they dont eat for awhile they will get hungry and then i suggest trying the pellets again. You can try flakes but they arent as healthy for them. I dont know why he would stop eating bloodworms if he previously was eating them. but like 2cute said he might be cold? oh and you dont have to put salt in. They live fine without it. although alittle is heathy for them.

Try putting him in a 1 gallon vase. If you need a small heater, add that. I did that to a boy bettas I have, he was in a 2-1/2 gallon tank and got stress stripes and acted moody, so I put him in a large 1-gallon vase. Now he's colorful, vibrant and perky as ever. I put a small heater in the vase to keep him warm as the weather is cooling down.