One of the most commonly available species of freshwater aquarium fish, the guppy is a long favorite amongst aquarium enthusiasts worldwide.

Flagfish are a small fish that are semi-aggressive in nature. These fish may not do well if multiple males of the same species are kept together.

Pacu fish are a large family of freshwater fish related to the piranha. While some species look like piranhas, they are herbivores and are peaceful fish.

Grunts are a family of saltwater fish made up of 150 different sub-species, some of which have been successfully introduced to the aquarium hobby.

Halfbeak fish are a type of marine and brackish water fish belonging to the family Hemiramphidae. They are a little less colorful than some marine species.

Danios are a popular species of freshwater fish in the aquarium hobby. They are characterized by two pairs of long barbells that hang from their mouth.

Lake Victoria cichlids are fairly aggressive fish. These cichlids are some of the most vibrantly colored freshwater fishes in the world.

Also referred to as wreckfish, reef fish, swallowtails and jewelfish, anthias are a large family of saltwater fish of over 200 different sub-species.

Referred to as breams, sea bream are a group of saltwater fish belonging to the Sparidae family. Most are found in tropical to temperate marine waters.

Grouper are a large family of saltwater fish characterized by their stout bodies and over-sized mouths. They are hardy, colorful and fascinating species.

There are several species of fish that carry the ""drum"" name. With more than 250 species, drum fish exhibit a wide range of colors and patterns.

The Moorish idol is closely related to surgeonfish. These fish are characterized by their vertically compressed, disk-like bodies and bold colorations.

Platies are fairly small fish, growing no more than 3 inches long, and they are very peaceful and non-aggressive. These fish are usually drab in color.

Koi are one of the most popular types of pond fish. Their bodies, which are long and powerful, are very similar to that of the wild carp.

A relatively hardy and easy to care for livebearer, the swordtail is one of the most popular aquarium fish species among beginner aquarists.

Squirrelfish are a family of ray-finned saltwater fish. They are characterized by their large eyes and long, sharp dorsal spines.

Saltwater Goby Fish are a large family of fish made up of over 2000 distinct species. Most species of saltwater goby fish are extremely small in size.

Betta Splenden fish are one of the hardiest species of freshwater aquarium fish and are an incredibly popular mainstay among hobbyists.

Wrasse are large family of saltwater fish made up of over 600 different species. They are also one of the most popular species of marine aquarium fish.

There are more than 250 species of Lake Tanganyika cichlids that have been identified, in a wide variety of colors and patterns.

The flounder is also known as a flatfish; a fitting name because its body is laterally compressed and it lays on its side, burrowing into the substrate.

Lionfish are a species of fish belonging to the scorpionfish family. They are known for their bright colorations, flowing fins and venomous tentacles.

The name porkfish is usually used to describe a particular species of grunt that can be found in the tropical regions of the world.

Cardinalfish are a large family of saltwater fish made up of over 200 sub-species. Most species are extremely colorful and are a couple of inches in length.

Saltwater eels are one of the most fascinating and demanding species of fish kept by aquarists. They are characterized by their long, snake like bodies.

Saltwater sharks are some of the most majestic and most dangerous species kept in the aquarium hobby. They are only recommended for advanced hobbyists.

Parrotfish are a marine fish with over 90 distinct species. They are characterized by their parrot-like beaks that are made of tightly compressed teeth.

Dottyback are a family of small saltwater fish made up of over 100 distinct species. They are hardy, intelligent and vibrantly colored, making them popular

Hap cichlids exhibit a wide variety of colorations and patterns ranging from solid blue to multicolored combinations of red, orange, and purple.

Seahorses are characterized by their equine appearance. Its upper body is shaped like the head of a horse and its lower body ends in an elongated tail.