Blue Groper
Blue gropers usually aren’t blue, they’re brown and they're not even gropers, they’re actually a type of wrasse.
But what's in a name? Well quite a lot in this case - unlike Gropers, Wrasse are all born female.
Female Blue Gropers are brown and they have to change sex to change colour. This process is clearly as difficult as it sounds – these fish turn blue in the process and pile on the kilos. But this only happens to the dominant female in any group, so most remain brown all their lives.
One big blue males can have up to 30 female mates, so if you see a Blue Groper look out for his harem of little brown ladies.