Strange Fish: 12 Unique Freshwater Aquarium Species


A majority of the freshwater fish tanks currently sitting in living rooms and bedrooms around the world probably hold traditional aquarium staples: guppies, goldfish and tetras.  And why not?  Popular aquarium species became so because they are cheap, readily available and (relatively) easy to care for.  But there are also plenty of unique and unusual aquarium residents.  Some of these fall into the realm of strange animals, while others are simply extraordinarily colorful or seemingly out of place in a freshwater aquarium.

The World’s Most Expensive Fish


(image via lerdsuwa)

The Silver Arowana (sometimes spelled “arawana”) is unique because of its large scales, slender shape, large size and short fins.  This South American river species has earned another distinction as well: A slight mutation caused one particular arowana to have a glowing white appearance.  The price tag for this fish was said to run into the tens of thousands.

Ghost Shrimp


(images via The Shrimp Farm and

This freshwater shrimp is often used as fodder for large aquarium fish.  They have recently become more popular as a pet because they are easy to care for and breed. Many fish-keepers find their transparent appearance quite unique and appealing.  Providing there are no predatory fish in the tank, these invertebrates will survive and thrive.

Lungfish and Gars


(images via fishindex, Karl Shuker, giveusahome, and  fish link worldwide)

Lungfish are thought to be related to early amphibian species.  Unlike most fish, they actually have lungs, allowing them to breath air.  These fish are hardy, if not comely.  They can survive in tanks with little or no aeration.

Gars do not have lungs, but have an incredibly thin, long body shape.  They are more difficult to keep than lungfish, but their quick movements and unique predatory behaviors make them attractive to more experience hobbyists.



(images via lee nachtigal and trebz)

You will be able to find some species of cichlids in a pet store.  Some, like tilapia, can be found at a grocery store.  Many of these fish have impressive colors and sleek shapes, traits that are usually reserved for saltwater fish.  Most species are only found in Africa’s Great Lakes (Victoria, Malawi, and Tanganyika).



(image via

This particular cichlid has earned a special place in the world of fish-keeping.  If they are kept in a large enough tank, they can grow to an impressive size.  Their mannerisms are not unlike those of a puppy: eating food from their keeper’s hand and responding to people on the other side of the aquarium glass.  Many fish-keepers claim that an oscar can recognize when the person who feeds them is near the tank.

Freshwater Rays and Channa Snakeheads


(images via uncle mike’s pet world and practical fishkeeping)

Freshwater rays are unique, if only because popular lore is dominated by their saltwater kin.  The freshwater variety can be quite large, requiring fish-keepers with larger than normal tanks and special know-how.

Channa (more commonly known as snakeheads) are a predatory fish with a unique shape.  Though they are prized in the aquarium trade, some consider them an invasive species.  Some were released from aquariums and have shown up in North American streams and lakes.  There is fear that they may disrupt the eco-system.



(images via fish index)

These common algae eaters are known for their unique, suction-cup-shaped mouth.  Aquarium experts will recommend them to any fish-keeper with an algae problem in their tank.  The way they attach themselves to glass and rock never ceases to amaze.

Freshwater Eel and Freshwater Lionfish


(images via, siamfishing, thatfishplace, petsolutions)

Freshwater eels are another species that seems out of place in a tropical tank.  Some of these species are small and snake-like, while others, like the freshwater moray, seem to have come straight from the coral reef.

Freshwater lionfish (slao called stonefish) are predatory fish that resemble their saltwater cousins in habit as well as appearance.  They use their unique physical traits as camouflage, sitting motionless, like a rock, until feeder fish (or misplaced tank-mates) swim close enough to eat.

Ranchu Goldfish


(image via lerdsuwa)

Goldfish have been bred to create uniquely shaped fish for years.  You may find bug-eyed, bubble-cheeked, long finned varieties out there, there are some, like the Ranchu, that are even more unusual.  This partiular breed is prized, though it seems to be lacking…a face (its eyes and mouth are obscured by the tissue that surrounds its head).