Fish

How can you tell a female fish from a male fish

Re : Fish

If you see one of them giving birth then it is a female fish, unless it is a seahorse when it is a male one.

Other than that I have no idea

Good question though as all fish look pretty much the same within a species don't they!

Re : Fish

I like the previous answer, yeah one way of knowing for sure is if they give birth Depends on the species of fish, for example with goldfish it can be very difficult to see any difference in appearance however females are generally plumper during breeding seasons and males can be seen pursuing the females by swimming by their sides. Generally females are duller than males for example in guppies, females have smaller rounded tails and barely any colour in their tails or on their bodies whereas males have larger more colourful tails as well as more colour on their bodies.