Chinese algae eaters
Another bad choice overall for all types of community tanks. Not only do they suck on the sides of fish, but they don't even eat algae. As they get older, they become more aggressive and seem to enjoy the taste of the slime coat of fish. Without this slime coat, all fish become more suseptible to disease. I do not recommend getting this fish at all.
Unless you're trying to make a female sorority tank (which needs at least 5 females), or having a divided tank, don't even think about trying to house bettas together. There's a reason why they are called siamese fighting fish, they fight with each other. Usually, in the wild where they live in thousands of gallons of water fights are not to the death as many people believe. In their homeland, whoever wins takes the territory and the loser swims away to live another day. In an aquarium, the loser tries to swim away but the tank too small. The loser is unable to escape and the winner continues the beating until the loser finally dies a painful death. Even a divided tank is dangerous since bettas are super athletic and can jump over a divider that's 1 inch above the surface.