Betta Fish

Siamese fighting fish, or betta fish, are a vibrant addition to any home and don't require lots of fuss or muss, but what do you really know about this fish? The pretty swimmers only cost a few dollars at the pet store and are happy contained in small tanks. But there are a few important things to know before bringing one home. Click through for interesting facts and a few helpful tips for taking care of your own betta.

Goldfish

The Common Goldfish is a type of carp. These hardy fish have been bred and kept in ponds and aquariums for centuries in Asia. They have an average life span of about 10 years. When goldfish return to the wild, they revert to their natural colors (green to black) in just a few generations.

Anatomy: This brightly-colored fish has orange scales and long, flowing fins. The average goldfish grows to be about 3 to 5 inches (8 to 13 cm) long. The largest goldfish are roughly 10 inches (25 cm) long.

Diet: Like all carp, Goldfish eat tiny plants and animals found rooting in the mud on the pond floor.

Great White Shark

The great white shark (Carcharodon carcharias) is a much-feared, streamlined swimmer and a ferocious predator with 3,000 teeth at any one time.

Anatomy: The great white shark has a torpedo-shaped body, a pointed snout, a crescent-shaped tail, 5 gill slits, no fin spines, an anal fin, and 3 main fins: the dorsal fin (on its back) and 2 pectoral fins (one on each side). Great whites average 12-16 feet long (3.7-4.9 m) long. Females are larger than males, as with most sharks. When the shark is near the surface, the dorsal fin and part of the tail are visible above the water. Only the underbelly of the great white shark is actually white; its top surface is gray to blue gray.

Diet: Young great white sharks eat fish, rays, and other sharks. Adults eat larger prey, including pinnipeds (sea lions and seals), small toothed whales (like belugas), otters, and sea turtles. They also eat carrion (dead animals that they have found floating dead in the water).

Great whites do not chew their food. Their teeth rip prey into mouth-sized pieces which are swallowed whole.

Classification: Kingdom Animalia, Phylum Chordata, Class Chondrichthyes, Order Lamniformes, Family Lamnidae, Genus Carcharodon, Species C. carcharias.

Seahorse

Seahorses are a type of small fish that have armored plates all over their body (they don't have scales). There are about 50 different species of seahorses around the world. They live in seaweed beds in warm water and are very slow swimmers. Seahorses can change their color to camouflage (hide) themselves in order to hide from enemies. The most unusual seahorse is the Australian sea horse, which has leaf-like camouflage all over its body, making it almost disappear in the seaweed bed.

Anatomy: Seahorses have a long, horse-like head (hence their name) and a curled tail. Seahorses range in size from under a centimeter long (Pygmy Seahorses) to about 1 foot (30 cm) long.

Reproduction: The female seahorse produces eggs, but they are held inside the male's body until they hatch; he is pregnant for about 40 to 50 days. The sea horse is the only animal in which the father is pregnant.

Classification: Kingdom: Animalia (animals), Phylum: Chordata, Class: Osteichthyes (bony fish), Order: Gasterosteiformes (armored, small-mouthed fish), Family: Syngnathidae (pipe fish), Genus: Hippocampus (meaning "horse sea monster" in Greek), and many species.

Guppy

Guppies exhibit sexual dimorphism. While wild-type females are grey in body color, males have splashes, spots, or stripes that can be any of a wide variety of colors.[10] The size of guppies vary, but males are typically 1.5–3.5 cm (0.6–1.4 in) long, while females are 3–6 cm (1.2–2.4 in) long.

A variety of guppy strains are produced by breeders through selective breeding, characterized by different colours, patterns, shapes, and sizes of fins, such as snakeskin and grass varieties. Many domestic strains have morphological traits that are very distinct from the wild-type antecedents. Males and females of many domestic strains usually have larger body size and are much more lavishly ornamented than their wild-type antecedents.[11]

Guppies have 23 pairs of chromosomes, including one pair of sex chromosomes, the same number as humans.[12] The genes responsible for male guppies' ornamentations are Y-chromosome linked and are heritable.[13]