Betta fish

Agreed, you need at least a 5 gallon for bettas, with a heater they are tropical fish and need temps of at least 78-82 F. You need a slow moving filter to prevent injury to bettas fins, but to also keep ammonia and nitrate levels down which could kill your betta. They love a few small live plants in the tank to hide amongst. Some good foods are hikari betta pellets, mabye 2 pellets a day only, and frozen bloodworms,brine shrimp, and daphnia. You can also check out ultimatebettas site for everything about properly caring for your betta, there is a misconception they live in mud puddles in the wild, this is far from the truth, so many pet bettas suffer from false information given by store workers, please do the humane thing and improve the housing for your betta, they can live up to 6 years!

Welcome to Project Noah Hadleigh!
Is this your pet fish? It is being kept in a very unsuitable environment for a tropical fish. It needs to live in a aquarium tank with proper heating, aeration & filtration. The bowl it is in has a very small surface area so the water is unlikely to be oxygenated sufficiently for him to stay healthy.