Some male fish control a ‘harem’ which is a group of female fish which he protects from other males and gets exclusive rights to breed with them but this is quite rare in fish (much more common in mammals).
Because most fish reproduce by ejecting clouds of eggs and sperm into the water (this is called broadcast spawning and involves virtually no care from adults), the dominant male is usually just the one who gets to the eggs first
Watch that video and you’ll see what I mean, a female races up from the group, followed by a bunch of males jostling to get their sperm there first. In reality, this probably means that the eggs are fertilised by lots of different males
I also wanted to mention that in some species, like clownfish (Nemo!), the female is the largest fish and she is the dominant in the group. All the other fish in the same anemone are smaller and they are males. When the female dies, the second largest fish (one of the males) turns into a female and becomes the dominant one.
P.S. Related fun fact: in Finding Nemo, Nemo’s dad Marlin should have become a female after Nemo’s mom died!
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Natalie commented on :
I also wanted to mention that in some species, like clownfish (Nemo!), the female is the largest fish and she is the dominant in the group. All the other fish in the same anemone are smaller and they are males. When the female dies, the second largest fish (one of the males) turns into a female and becomes the dominant one.
P.S. Related fun fact: in Finding Nemo, Nemo’s dad Marlin should have become a female after Nemo’s mom died!
fishjunior commented on :
fishjunior!