Not one but 31 facts I bet you didn't know about Fish

I was doing a research project a while back and I remember finding some really interesting material about fish.

1. There are over 21,000 species of fish and 15% of the fish population does not have an acid producing stomach.
2. Then are several species, such as the teleosts that have two or more stomachs, usually the second stomach will be used to store gravel for digestive purposes.
3. A few species of fish actually build a nest; the stickleback is one of them. They nest in the weeds.
4. Sunfish are prolific creatures; they can lay over 300,000,000 eggs at one time.
5. We are all aware that male seahorses lay the eggs, the females simply deposits them in their pouch.
6. Scallops swim at amazing speeds by clapping their upper and bottom shells together.
7. There are fish that are capable of living out of water. The African lungfish burrow underground for up to four years while the wait for the water to rise again.
8. Catfish have over 27,000 taste buds.
9. The Octopus has 4 hearts.
10. If a goldfish is kept in running water or is left in dim light it will change colours.
11. A goldfish has a rather long lifespan; it can live up to 40 years.
12. The poor starfish has no brain.
13. Starfish have eight eyes. They have one eye at the bottom of each leg.
14. Starfish can have up to 16 arms.
15. The Leatherback sea turtle is huge, weighing in at 1,500 pounds.
16. A Slug actually has four noses.
17. Clams and oysters change sex, clams start as males and then become female. Oysters can change sex several times during their lifespan.
18. Oysters grow in the root of mango trees that are exposed once the tide goes out.
19. The tiny snapping shrimp (1 and a half inches long can make a sound with its claw that sounds like a firecracker.
20. Coconut crabs will actually climb the coconut trees to eat.
21. The electric eel can send out 650 volts of electricity, which is stronger than the current in an average wall socket and it is strong enough to make a horse stumble and fall.
22. No wonder lobsters are so expensive. They grow so slowly. It takes about 7 years for them to grow to one pound.
23. Eels do not get enough oxygen under water and they come up for air about every five minutes.
24. The Scallop has 35 blue eyes.
25. The Pacific giant octopus is the size of a pea at birth but watch out it grows up to 150 pounds and 30 feet long within two years.
26. The giant squid weighs up to 5,000 pounds and measures about 55 feet across. It is one of the animals missing a backbone. Some scientists claim the giant squid is a myth; not a living creature.
27. The eyes of a giant squid are 16 times bigger than that of a human. Their eyes are more than a foot wide.
28. The Jellyfish is made up of 95% water. Some of them have eyes as large as their stomachs.
29. Flying fish will glide along the wind current up to 20 feet in the air.
30. A Narwal whale is about 14 feet long with a tooth about 8 feet long.
31. The pygmy goby is the smallest fish in the world. It is only a half an inch long.

Sources:

http://www.funshun.com/amazing-facts/fish-animal-facts3.html

http://www.rusticgirls.com/fun/neat-facts-about-fish-other-sea-life.html