Fish Facts

Weirdest Freshwater Aquarium Fish

Here are 26 fish that are weird and rare freshwater species you can add to your fish tank to create a different and unique look into the aquarium.

Weirdest Freshwater Aquarium Fish

Adding unique fish into the aquarium is the passion of almost all aquarists. Differently-shapes and colored fish can add so much drama into the tank. Weird fish are not generally the choice of many hobbyists, but some want to add the uncanny and strange fish into their home aquarium to draw attention. 

Weird or strange does not mean ugly, as a fish can be strange and beautiful at the same time. There are several freshwater aquarium fish that are strange and weird but equally beautiful and attractive. 

1. Electric blue jack Dempsey’s

Electric blue jackfish or Cichlasoma octofasciatum is one of the most beautiful fish and strange fish in coloration. The fish is attractive and appealing due to its electric blue color. The fish has its origin in Central America, and it is not too demanding and easy to take care of and handle. 

It has sparkling neon, metallic blue to green scales throughout the body that sparkles when swimming in the water. The body is compact, the male having pointed anal and dorsal fins.

The size ranges between 6 to 10 inches, and the females are smaller than the males. Their natural habitat is full of plants with temperature ranges between 26 to 30 degrees celsius. The fish is rare and strange for most aquarists and is slightly aggressive. 

2. Flower loach

Imperial flower loach or Leptobotia elongata is another strange fish that does not look like typical loaches. The fish is long and extends to some feet or 30 inches. The head is flat and tapered in shape, and there are irregular stripes or patches of dark color on the bright yellowish-golden body base. 

Its natural habitat is running river water, which has sufficient oxygen level with rocks at the bottom. The fish is semi-aggressive is not suitable for beginners. It is the largest species of the loach family but is very uncommon. 

Due to its large size, it is preferable to keep it in a large tank of about 200 gallons. It can eat all the small fish in the aquarium because of its predatory nature. Keep them with the same size species and similar tank conditions as natural habitat.

3. Red bulu point fish

Petrochromis sp is the scientific name of red bulu point fish, and it is weird in appearance. It is native to Africa and is too unusual and strange due to its different colors. The orange to red color is too bright and sharp that sometimes looks too weird but is unique.

Usually, males are brighter in color, and the females are dull, having brown and orange patches on the body such as the face, belly, and cheeks. They are not aggressive but are extremely expensive due to their unusual appearance. 

They grow up to 25 to 27 cm and need open spaces in the tank for swimming, which means you have to set up a large tank for them. Most hobbyists avoid keeping them in their aquariums due to the fear of raising aggression in other fish species in response to their bright color.

4. Zebra shovelnose catfish

It is a species of catfish but is not like typical catfish and look too unusual. The fish is weird due to the shape of its mouth, which is extremely rare. The body consists of dark and light stripes that run horizontally throughout the body. The fins also have the same color-stripes as the body, and only the head part lacks color-stripes.

It has a flattened nose, which is long and elongated. Unlike other catfish, the overall look of the fish is bold and loud. It is too expensive, and most people, unlike it and call it a monster fish. It also eats small fish in the aquarium is very large, approximately 24 inches.

The temperament of zebra shovelnose is not peaceful, making it an unsuitable tank mate for most fish. This large catfish is native to South America, Brazil, and Colombia and love to live and swim at the bottom of the tank.

5. Golden gar

Golden gar is too attractive, having a bright golden-yellow body but is weird and uncommon due to its body shape. It looks extraordinary in an aquarium due to its too long, extending snout. The body is also too long and slim with bright, sunshine-like orange to yellow color.

The golden bar looks good but is unusual and weird due to several reasons. The fish has a strange body appearance, high price, and large tank requirement that makes it unacceptable for most fish-keepers. 

The fish seems to threaten other tank species as it can eat small fish such as sunfish, crayfish, and other small-sized crayfish. The fish is suitable for large tanks due to its large body size.

6. American flagfish

American flagfish is very rare and unique, considering its body coloration. It is a killifish that loves to eat algae and has strange color patterns. The body has scales having different colors on it like red, green, purple, and blue. 

The unequal distribution of color throughout the body makes it look like a flag, which is too different and weird from other fish species. They are easy to care for and can live in smaller tanks with many other tank mates.

The reason for calling it weird is the unusual, American flag-like appearance of the fish that does not match with any other fish of freshwater. The scales are iridescent and give different shades when light strikes them. Also, it is uncommon for many home aquarists.

7. Peacock gudgeon

The peacock gudgeon is very common among hobbyists, but it has strange body patterns that make it fall into a weird category. The fish is peaceful, easy-care and requires low-maintenance, and is preferable for small tanks.

They have multiple color stripes of neon red, blue, and yellow color on the body that runs vertically. The fins are yellow, but the body has the iridescent distribution of red and blue. The eyeball is prominent and large, the head is round, and the tail has the same yellow color. 

It grows up to 2 to 3 inches and can live up to 4 to 5 years in the aquarium when getting suitable water conditions and tank environment. They live peacefully with other tank mates from different species.

8. Bristlenose plecostomus

Bristlenose plecostomus has an entirely weird, loud, and patterned look. It is a catfish that is unusual from all the other catfish and gives an odd-look. The fish has patterns all over the body, including head, fins, tail, and even eyelids. 

The fish is not aggressive and is an herbivore with a small size, 3 to 5 inches only. The color may vary in different species, including brown, olive, green, gray, and yellow. It may have white spots on the body, but usually, it has full patterns in light and dark contrasts.

It has a slightly flattened body, a long and broad head, and slightly-elongated lips. The body has bony plates and tentacles on the head, which have the same pattern as on the body. They love to live at the bottom of the tank; they also have a habit of sucking on a different object.

9. Bolivian ram

Bolivian ram or red ram is peaceful fish but is very difficult to care for and handle. The fish looks like a butterfly and has the beautiful coloration of golden, brown, and red. Unlike all other fish, they form pairs in the tank and live with each other throughout their life.

The body also exhibits pearl-like turquoise hues on the fins and has some black spots on the body. The fins also have brown to reddish highlights. It is an omnivore and extends up to 3 to 4 inches, which makes t suitable for small tanks.

The fish is tropical and can live calmly in a tank having similar water parameters and conditions as their natural habitat. It is an omnivore and has its origin in South America and brazil.

10. Indian glassfish

Indian glassfish is too rare fish and has an entirely different body appearance. The fish has glass-like transparency with a small size of 4 to 5 inches. They look strange and different swimming in the tank and sometimes confuse their owner in clear water due to transparent body.

It is present in India, Pakistan, Thailand, Myanmar, and Nepal and loves to live in groups. These unusual creatures are peaceful but can eat other small fish in your aquarium. 

Due to their clear and transparent look, they are not acceptable by many tank owners. Before adding to the aquarium, one must establish a planted tank with bright colors and dark color substrate to compliment the fish and make them more visible. 

11. Crowntail betta fish

Crowntail betta is another unusual and strange fish but is too active and playful. Despite their different appearance, they look beautiful and can add so much drama to a tank. They have different shades and color that includes blue, red and purple.

The tail of the fish is too extended and huge-sized that draws attention. The fish-tail has a length of 7 to 8 inches. It is an easy-care fish but is sensitive to fluctuations in the water conditions. The size of the crowntail betta fish ranges between 1.5 to 2.5 inches. 

The tail fins look like several rays and strikes moving and waving inside the water. This feature differentiates it from other betta species.

12. Royal whiptail catfish

The royal whiptail catfish is a species of catfish family that is very weird in look. It has a long and sleek tail, round head, and elongated nose. The fish is equally strange and helpful as they suck up the algae from the aquarium. 

It lives at the bottom of the aquariumk and is a calm fish that does not create trouble for other animals. It has an overall thin green, yellow, and brown color mix body. It is an omnivore and not too socially active. 

The fish grow up to almost 6 inches and can live for a comparatively long time. It is not too tough to handle the whiptail and is manageable due to its hardy nature. Many plants, rocks, and driftwood can help you keep it healthy in the aquarium. 

13. Ghost glass catfish

These weird fish have a clear and transparent body that can disappear in the tank. The fish look like a clear-glass that needs some color additions like rocks, colorful gravel, and plants in the tank to become prominent. It lacks dorsal fish and has a large and prominent eye.

It is a peaceful fish and loves to live with 4 to 6 instead of staying alone. It looks stunning as you can see the body organs of the body through a transparent body. It needs some care to remain healthy and easily stresses if there are no hiding places in the aquarium. 

It is playful in low light conditions, and too much light can stress them. It does not grow more than 6 inches and mostly remains at a size of 3 to 5 inches. Unlike other catfish, ghost glass catfish like to swim in the middle of the tank.

14. Lungfish

The lungfish is also a weird and strange fish that is uncommon and unpopular. The name indicates that it has lungs, unlike most fish, and does not require high oxygenation levels in the tank. 

It belongs to the class sarcopterygii and is present in the rivers and lakes of Australia, Africa, and America. It has a slim, thin, elongated body shape having pectoral and pelvic fins. The body has intricate, the irregular lining of bright color, which makes a different pattern.

They have a flattened-shaped head and mouth with a round, long body. It is grayish and has black spots on the head and body, and some species have patterned bodies. It has round-crushed teeth that help to chew food, which is a rare feature.

15. Ranchu goldfish

Ranchu goldfish or king of goldfish is too much weird fish, and it is hard to believe that it is a goldfish. The body shape is too strange and different from atypical goldfish. It has a bubbled, buggy growth that looks like overgrowth on the face of fish. 

The face features of the fish are not visible due to the overgrowth and bubbles around the head. It looks like the fish lacks eye or mouth. The fish is rare, uncommon, and unpopular due to its body appearance and high price.

It has a short, rounded, egg-shaped body with slightly broad tail fins. It does not grow more than 5 inches and can live for a very long time. It has different colored varieties that include deep red, yellow to orange, white-gold, and some can be all white.

16. Chaca bankanensis

The chaca fish has a body that looks like a leaf in terms of both color and shape. It is one of the weirdest fish that lives in the bottom of the tank. It is a predator that eats up small-sized fish. The fish has an average size of 5 to 8 inches.

The body looks like a tadpole having a tapered, compressed posterior end. It has horny skin of dark brown to a black color and black patches on the body. It has round-shaped caudal fins, and the dorsal fins are small. 

The fish is uncommon in most freshwater aquariums due to its predatory nature and strange appearance. It is not playful and active and looks like a dead leaf on the bottom of the aquarium.

17. Panda loach

Panda loach is another unusual addition to the aquarium due to its strange panda like body patterns. 

It is present in china and is habitual of living in moving waters, and one needs to create a strong water current in the tank to mimics its natural habitat. 

Their body has stripes or mottled pattern in white, brown, and black color. The fish looks like a small panda with an average size of about 2 to 2.5 inches. 

Moreover, it requires proper oxygenation and hard water and is not generally preferable for beginners. Panda loach is a rare and uncommon freshwater fish species despite its peaceful nature. 

18. Boleophthalmus boddarti

Boleophthalmus boddarti, or blue-spotted mudskipper is too weird are strange fish that is not common among aquarists. It is habitual of living on very soft mud, as the name indicates. The face is round, and the tail is elongated and long.

The fish is large with an approximate length of 20 to 22 cm when adults, but some remain too small with only 7 to 9 cm. It is brown having irregular, stripes or bars of blue color throughout the body. 

Having an aggressive nature, it forms territories and does not allow other males to invade their territory. It is present and distributed in southeast Asia. The fish looks too strange and weird and is not a choice of fish-keepers at all.

19. Rope fish

From the name indicates, the rope fish has a rope-like body shape that is long and extended. This peaceful species is friendly and easy-care, requiring low-maintenance. The head is slightly flat while the body is round and has scales on the body. 

The body color looks muddy, yellowish, or brownish and the average size reaches up to 20 to 25 inches. It also has some dark color spots on the body and has tentacles on the face. The fish is rare in having both lungs and gills and can breathe efficiently. 

 The fish appears like a snake swimming in the tank and has predatory nature. The overall textured and patterned body looks completely different from all the other species in any aquarium. 

20. African butterflyfish

The fish has its origin in Africa and looks like a butterfly in appearance. Unlike all other fish, butterflyfish have fins that exactly looks like butterfly wings. It gives a view of butterflies of dark colors swimming in the water. 

The dorsal, tail, and pectoral fins all contain an outline of dark brown color, while the central part has patterns of different colors. The body is dark brown to greenish and has black spots or patches all over.

It grows up to an average length of 4 to 5 inches. The mouth is round and frown-shaped and can feed on small fish and invertebrates.

Butterflyfish is relatively uncommon in home aquariums due to its sensitivity to fluctuating water parameters. They love to live in planted aquariums having floating plants, and swim just below the water surface.

21. Elephant nose fish

This weird has an elephant nose, which looks unusual and unique. Its trunk-like mouth helps feed and protect it, and the fish is too active, especially at night. This fish gets its food from substances present in soil substrate.

The body color is a mix of black and gray, and the whole body has the same color, including the mouth, fins, nose, and face. The long, thin body has a narrow head and has the same size dorsal and anal fins. It uses to hide in the day time because of its shy nature.  

The fish has a rare feature of detecting the electric current with several receptors on their body. This feature helps the fish to find food, communicate, and to change direction in the water. Elephant nose grows to about 9 inches and is not preferable for beginners.

22. Chinese hillstream loach

Like all other loaches, they are also algae feeders that help cleaning the algae overgrowth from the tank. Living in groups of 3 to 5 fish, they usually dwell at the tank bottom. They possess a thin, flat body of yellow and black color and are smaller in size, generally 2 to 2.5 inches.

The fish usually look like a pleco but is entirely different. The fins are transparent, and the body has black dots all over. The fish has a weird body shape due to the presence of barbels around the mouth. 

They inhabit to living in fast-moving water, therefore, requiring strong water current in the tank. Having a peaceful and calm nature, they are suitable for most of the aquariums having different species. 

23. Snakehead fish

This rare fish has a strange head shape that exactly looks like a snake. One can never recognize that it is a fish when considering the face only. Their body is long and eel-like, with a flat head having scales.

The overall body texture also looks like a snake due to snake-like patterns. Moreover, the body grows longer and is not suitable for smaller tanks. Also, one need legal permission to keep the snakehead in the home aquarium.

Like snakes, the snakehead is predatory that will eat up small fish in the tank. The body has dark color patterns on the light tone base with round, prominent eyes having a jet black pupil. 

24. Flowerhorn

The flower horn fish has an odd-shaped head. It is not a natural fish breed but a cross-breed of two different species. They come in different colors and breeds such as golden monkey, Thai silk, king kong parrots, golden base, others.

Orange, blue, red, white, green, silver, and other colors are common in different species. They are man-breed species, so their life span is also long that is up to 12 years. There is a ball-like overgrowth on the head of the flowerhorn, which is brightly-colored. 

Despite their semi-aggressive nature, they are quite interactive with the owners. Although the look is strange, it is getting popular day by day due to bright coloration and patterns.

25. Black ghost knife fish

As the name indicates, the knife fish possesses a thin, flat, knife-like body and is entirely black. They are not friendly and spend their whole day hiding. Also, it is a carnivore and can eat up all the small fish in the aquarium.

Having a semi-aggressive nature, the fish do not like to coordinate with other tank mates. The body lacks scales and is a bony fish that grows up to afoot. The tail looks like a blade that has unusual or irregular body extensions along lateral sides.

It need advance level care and is not desirable for beginners. A large tank setup is suitable for knife fish having reduced light sources. 

26. Arowana

Arowana is the world’s most expensive and weird fish due to their awkward appearance. The fish has a slender-shaped body and very short fins. The body has scales all over and is silver-white. It looks entirely different from all the species of freshwater fish.

The body size increases up to 4 feet and has a full, heavy body. It is a predatory fish that hunt and catch all small fish. The mouth has a drawbridge shape, and the body displays golden highlights when light strikes. 

These semi-aggressive fish can live up to 15 or more years when living in ideal water conditions. Only experienced fish-keepers can keep them in the home aquarium, or the fish may die of poor care.

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