New to keeping fish

[Valarie]

I have a betta and 3 cory albino catfish. The betta I believe attacked and killed 1, which I replaced with 2 . So now it's 3 against 1 . However, one of the catfish
looks sluggish and not moving much. She/he also for a time had a hard time reaching the bottom of the tank. The
lady at pet smart thought the fish might have swim bladder syndrome and suggested peas. Any other diagnosis or
suggestions?

 

[fluttermoth]

How big is your tank? How long has it been set up and do you know if it's cycled? How big and how frequent are your water changes? Is your water hard or soft? Have you tested the water for ammonia, nitrite and nitrate?

Sorry for all the questions, but there's not enough information for us to go on in your first post.

'Swim bladder syndrome' isn't a disease in itself; it's symptom that can have many causes, a bit like 'backache' or 'stomach ache' in people.

If you suspect your betta is attacking other fish, you should really keep him on his own. On another note, corydoras are very social and should never be kept in groups of less than six.