Clown Anemonefish

Made famous in the movie Finding Nemo*, the Clown Anemonefish is one of the reef's most-popular inhabitants. Like most anemonefish, this species lives in a matriarchal group, with the largest member being the dominant female. She is the only female, and she mates with just one of the group, all of which are males. If the breeding male dies, one of the lesser males is promoted to his place. If the dominant female dies, the 'alpha'/breeding male changes gender and becomes the dominant female. Then one of the lesser males takes his place.

*Actually, the movie and this species are 'just Hollywood' because Amphrion ocellaris lives in SoutEast Asia and the very northern parts of Australia, but the movie is set in Sydney. There's another species that lives off the coast of Queensland, which is Amphiprion percula. A.percula and A.ocellaris are distinguishable by percula having thicker black stripes separating their orange & white areas.