There are many reasons why cichlids behaviour becomes aggressive. It can happen when another fish encroaches into their territory or tries to steal food or a potential mate. In such cases, a cichlid shows aggression by flaring its gills and spreading its fins to make it look as large as possible. If the other fish isn’t deterred, one may progress to tail beating in which a cichlid attempts to show its strength by pushing water at its rival. This escalates to a face-to-face combat, which includes mouth wrestling and lip locking and, finally, chasing each other in a circle and attempting to bite the other.
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