In 2017, researchers at Ghent University in Belgium identified several common issues regarding betta fish welfare. They wrote that bettas can become stressed from sharing a tank with fish they see as rivals, especially when they are confined and can’t escape, or from seeing them in other nearby tanks. Too-small tanks, a lack of environmental enrichment, and mycobacterium infections also harm the quality of life for many bettas.
Christel Moons, one of the authors of the paper, explained that it’s especially important to set up a tank where the betta has companionship with fish that it gets along with and also has the option of avoiding them. “You want to look at species compatibility and you also want to make sure that it has the option for hiding,” Moons said. “Having said that, it’s the same for all fish.”