Bettas are territorial fish, and they can be aggressive towards other fish, especially those with long fins or bright colors. It's important to choose tankmates that are peaceful and non-aggressive.
Bettas also prefer warm water, so it's important to choose tankmates that can tolerate the same water temperature.
Some good tankmates for bettas include:
* Neon tetras
* Cardinal tetras
* Rummy nose tetras
* Zebra danios
* White cloud mountain minnows
* Otocinclus catfish
* Corydoras catfish
* Cherry shrimp
* Ghost shrimp
It's important to do your research before adding any fish to your betta tank. Make sure the fish you choose are compatible with bettas and that they can tolerate the same water conditions.