5 mixed size Berghia are perfect for eliminating aiptasia anemones.  This is the only thing they eat.  These nudibranch are nocturnal. Therefore, you will only see them about an hour after the lights go off in your aquarium.  Rule of thumb needed for a tank is 1 berghia per 10 gallons of water. It will take the Berghia a couple months to eliminate all anemones. Free shipping with this package only.