Hi there, Trienchieu!
I think you might be feeding a tad bit too much. I usually do 4-5 pellets once a day, not 2 times.. So maybe limit it to 4-5 pellets?
I would also suggest getting some freeze dried bloodworms.. They come in little cans like the pellets and are a yummy and healthy treat for the fish! Once or twice a week, give your fish one big bloodworm and two pellets. And every regular day, feed the 4-5 pellets. So 4-5 five days a week, and lets say, saturday and sunday feed them two pellets and one worm.
Good luck with your fishy! :)