Dusky farmerfish

Stegastes nigricans
Poisson-fermier à tache noire
‘Atoti (Society)

Interesting facts

This fish is very territorial and can be very aggressive towards intruders larger than itself. Cases of bites against divers and swimmers have already been reported. S. nigricans practices a form of agriculture with a species of red algae. The fish will claim a patch of "brown carpet algae" which it defends by chasing away other fish and sea urchins. The fish also pulls up other bits of algae that attempt to grow in the patch and swims outside of its territory to spit the invading algae out. When the fish claiming a patch is removed, the patch is eaten up within a few days.

sources

P. Bacchet, T. Zysman, Y. Lefèvre, 2010. Guide des poissons de Tahiti et ses îles. Au vent des îles. 3e édition.