I have a double tail betta named Phillip. I love him to death and he is usually very active. He loves to swim around and just watch me feed other the other fish and watch me work on home work for college. But within the last 48 hours or so he has become very lethargic and hiding a lot.
He refuses to eat his flakes so I have had to change his water every day just to make sure it stays clean. I also put the water cleaner and stress coat it, but it still he is hiding and not eating. I will admit I have still yet to get a heater for his one gallon tank and the water temperature stays around 74-76 degrees. It has been that way since the beginning though. Also along with the lethargic and non eating he seems to be gasping for air a lot and staying on the bottom of the tank instead of his little fish hammock that he used to love. I have searched every where to help him, but I can't figure it out. By the way, I have had him for almost a month now.
Also, fish flakes are not really good for bettas. Any food for betta should have fish listed first as the ingrediants, and very little (if any) cereal filler.
Bettas are carnivorous fish... in nature, they eat insects and little fish.
Specially formulated betta pellets are usually a good food to start with. Your betta can only eat one or two pellets twice a day, max. Their stomach is only as big as their eye! Fasting one day a week also helps to keep their tiny little digestive tracks flowing along smoothly.
If you are feeding flakes, or too much food, or both, that will affect water quality and the betta's health.
If you fish is having trouble breathing and his unheated tank is under one gallon, reduce the water down until it just covers him, so he doesn't have to struggle to breathe - he just has to reach up.
You said you had other fish? If they are in a tank heated to about 78F, float the betta (just barely covered in water) in a container in the bigger tank. Tape it to the inside of the tank to a tank wall, so it can't be tipped over.
We want your fish to be warm and make it easy for he/she to breathe.
I am hoping some (all of this) will be helpful to you. Good luck to you and your fishy! If you need more assistance, feel free to ask more help. They are many people on the board who'll be happy to help. :)
His tank is a gallon and unfiltered. I'm going to by a heater tomorrow for him after school lets out.
About the food. I have these flakes that are for Bettas. It is by BettaMin. It has fish in it. I have also tried to feed him pellets, but I think they are to big for him. He will try to eat it then do a weird head bob thing and then spit it out and not touch it again.
I also have a larger ten gallon tank that stays around 80 degrees for my sunfish and moon fish. I will put him in there right now and hope that he doesn't try to attack the other fish through the plastic. That would be horribly sad.
Cover the betta's container with plastic wrap (but be sure he can get air). That will keep him from jumping out, and the other fish from jumping in.
Pellets can be too big if the fish is small... easy to fix... put some pellets in a freezer bag, and wack with a hammer until the pellets are smaller. Soak the pellet pieces in some tank water (in an cup that hasn't seen soaps, etc) until they swell/soften. Then feed to your betta! :)
I'm heading to bed now... but if you have more questions, ask... keep an eye on your betta... note any changes... hopefully he will feel better soon