Betta fish are known to be aggressive and instinctively territorial, so it is important to choose tank mates that are peaceful and not too colorful. Here are some fish that can live with bettas:

• Rasboras: These are gentle, peaceful fish that tend to keep to themselves and do well sharing an aquarium with a betta fish.
• Ember Tetras: These are small, peaceful fish that can be suitable tank mates for bettas.
• Kuhli Loaches: These are docile, eel-like fish that can make great scavengers for picking up any excess food your betta drops. They tend to hide together in groups during the daytime and come out to play when the lights are off.
• Cory Catfish: These are peaceful and easy to get along with, making them ideal tank mates for a betta fish.
• Dwarf Frogs: These are peaceful and interact very little with bettas, making them a good choice for a tank mate. They prefer living in small groups of two or more and like to explore their surroundings.

It is important to note that not all bettas will get along with tank mates, and each betta has a unique personality and temperament. It is recommended to provide hiding places and plenty of space for betta fish to explore, hide, and rest. Some fish species with bright colors and large flowing fins should be avoided as they may trigger betta fish and cause them to attack. Additionally, predatory fish and those with territorial and aggressive tendencies should be avoided.