Basic Information

• Betta fish will attack goldfish, so avoid them as tankmates.Jupiterimages/Photos.com/Getty Images
  
  Betta fish are part of the Gourami family. They prefer fresh water of about 75 to 80 degrees, but they can handle a tank anywhere above 65 degrees. Bettas are less active than other fish and can be picky eaters. Strong currents from filters will make them hide in a calmer section of the tank. Bettas tend to be quite shy around other fish, in part because some fish like to chew on their large fins. The best tankmates for a betta are smaller, slower and less aggressive fish, unrelated to the Gourami family, that are capable of living in a warmer tank.
  
  

Tank Preparation

• Keep a top on your aquarium, not only because betta fish are known jumpers, but also because they live on the surface of the aquarium.Janie Airey/Lifesize/Getty Images
  
  A betta fish prefers a little isolation and needs a place to relax away from tankmates. Use at least a 10-gallon tank if you intend to build a community with your betta. Put tall plants in the corner farthest away from the filter for his territory and add additional plants in front of the filter to decrease the strength of the current. If you don't have a heater to maintain a 75 to 80 degree water temperature, make sure that the room itself stays fairly warm.
  
  

Picking Roommates

• Avoid significant differences in sizes when picking tankmates for your betta.Jupiterimages/Photos.com/Getty Images
  
  Docile, slower fish are ideal tankmates for a betta. Consider platies, moillies and slower tetras such as neons, cherry barbs and cory cats. Angelfish are acceptable in larger aquariums. Avoid overstocking the tank; bettas take a while to eat, so faster fish such as danios and rosy barbs can leave your betta hungry. Invertebrates like glass shrimp can make an interesting community; they stay in the bottom of the tank and zip away before a betta can pick on them. Smaller bottom feeders and African Dwarf Frogs are other good tankmate options.
  
  

Bad Combinations

• Goldfish pollute tanks quickly, and bettas prefer a clean living environment.Jupiterimages/Photos.com/Getty Images
  
  Avoid goldfish and guppies; your betta may confuse them for a male, and attack them. Goldfish prefer colder water and pollute water more, so they make terrible roommates in general. Fin-nippers such as danios and tiger barbs will ruin your betta's fins and eventually kill him. Your betta will likely eat tiny or baby fish and will be afraid of larger active species like giant danios. Keep the balance by introducing fish slowly, and watch their interactions carefully. If the betta's fins become clumped, he's stressed or ill; move him to a hospital tank.