 They swim mainly in the upper and middle water layers and are highly sociable fishes, mixing well with other types of tetras and tropical fish in general, so are often kept (like many other tetras) in a community tank.However, they will tend to nip at the fins of fish with long, wavy fins, such as angelfish or guppies.Bloodfin tetras have also been kept in cold-water tanks, provided the temperature does not drop below room temperature.