Researchers at the University of Padova, told Discovery News that “fish can distinguish between larger and smaller quantities, with an additional ability to ‘count’ up to three, according to research on tropical angelfish. Fish, as well as dogs, probably have even more advanced mathematical ability, scientists suspect, but we need more methods to better study these animals.”
The tropical reef fish on our Sex Change Cam have another trick up their fins as well. Most of the animals in there are members of the wrasse family, which generally start life as a female and then, depending on the number of males in a given area and the aggressiveness of the individual female fish, may change into a male. It’s a one-way trip and they don’t change back. Ergo, the name “sex change”.