Muelleri Butterflyfish - AustraliaChelmon muelleri The Butterfly is fairly hardy and adapts well to life in an aquarium if acclimated properly. Most butterflies in this genus can be added in a group. They wont do well with fish that are overly aggressive, but they will also nip and pick at fish that are very timid. Finding ideal tank mates can be a challenge. Initially, butterflies can be shy; making sure there are plenty of hiding places will help them acclimate. Butterflies are not