Mainly balance and locomotion. Some use them to attract a mate.
The main function would be for fish to be able to see. Providing them the ability to sense food, predators, mates...etc.
It is to balance the fish in the water.
yes
They do
Mermaids have the upper bodies of women and fish tails.
no fish don't have legs they have tails and gills.
fish hit the ground with there tails
fish tails
they both have tails
No. Sharks, being fish, have vertical tails, while whales, being mammals, have horizontal tails.
Don't now
Its quite simple to breed cold water fish: The main thing you need for breeding is a moss plant they are dark green and quite smelly, moss plants contain small worms in them that swim around in the tank. Its always important for the tank to be the right temperature but its not a main priority they can still breed if the temperatures not completely right. To tell the sex of the fish all you have to do is look at there tails. males have smaller tails than females. To get a simple breed of fish try mixing together a fintail fish with a common goldfish.