many of the advice that has good scores are on the money. it is going to be counted on the betta and tank length. A betta can tend to be extra aggressive in a small tank of much less thab 5 gallons. good tank friends- -cory cats -small sucker fish like otto, and in bigger tanks small breed pleco, and Siamese algae eaters (no chinese language algae eaters) - non showy platty, and swordtails. Guppy, and molly could nicely be a showy. stay away from somewhat fancy male guppies, and male sailfin molly. Fish to stay away from- - different betta male or woman. maximum betta agression is betta on betta. a pair will mate, and then attempt and kill one yet another. (from time to time skipping the mating.) -Barbs, and better tetras. Neon are many times no longer fin nippers. -Gourami are too aggressive and/or too beta like. -Angelfish. Too sluggish, super fins, and intensely aggressive later in existence. -Semi-aggressive, or aggressive fish. Betta are undesirable swimmers, and surely picked on. -super sluggish shifting fish as male betta are particularly undesirable swimmers, and in a bigger tank maximum fish can out swim a betta a cover. A betta will many times take an afternoon or with the point to get use to a tankmate. A fish like a goldfish can run or cover.