Rarest Fish in the World

10 Rarest Fish in the World that are extinct soon


As fishing continues to increase in popularity, the negative impacts on marine species are evident. Unfortunately, here are several species of fish that are now increasingly rare to find in the wild. 

Through protective efforts brought upon by conservationists, many species have been able to make somewhat of a recovery. Still, it is essential to understand the impacts of overfishing on the species’ natural environment.

Between scarcity through overfishing and natural rarity, there is nearly a never-ending list of rare fish. Check out our list of the 10 rarest fish in the world.

Top 10 Rarest Fish in the World

Whether you want to stay up-to-date on species with a dwindling population or you want to work to protect rare species and take a stance, our list of the rarest fish will give you incredible insight. 

1. Ornate Sleeper-Ray (Electrolux Addisoni)

The ornate sleeper-ray is a rare species of electric ray and is currently the only member of the Electrolux genus.

Where Are They Found

Only a few ornate sleeper-rays have ever been seen in the wild, but they are native to the coast of South Africa. The rays are in four recorded locations:

  • Coffee Bay
  • Eastern Cape Province
  • Durban
  • KwaZulu-Natal

How Many Currently Exist

Because the ornate sleeper-ray has only been observed in nature a handful of times, researchers do not know precisely how many adults of the species exist.

Fun Fact

The ornate sleeper-ray belongs to the newly discovered Electrolux genus named after the Electrolux vacuum cleaner company. 

2. Sakhalin Sturgeon (Acipenser Mikadoi)

The Sakhalin sturgeon, or Acipenser mikadoi, belong to the fish’s sturgeon family, dating back to the Late Cretaceous period.

Where Are They Found

Typically found in brackish waters, the Sakhalin sturgeon live in the Pacific Northwest and Russia, northern Japan, and Korea. 

How Many Currently Exist

The Sakhalin sturgeon faces multiple threats in their natural environment, including:

  • Illegal poaching
  • Trawling
  • Accidental bycatch
  • Pollution
  • Dams

As a result of these devastations to the population, there are no concrete records of how many exist today. Approximately 10-30 adult Sakhalin sturgeons spawn annually.

Fun Fact

The most enormous recorded length of a Sakhalin sturgeon is just shy of five feet at 59 inches.

3. Red Handfish (Thymichthys Politus)

The red handfish, or Thymichthys politus, belong to the Thymichthys family, which contains fourteen different species. 

Where Are They Found

The handfish genus is native to Eastern Australia and Tasmania. The red handfish, in particular, was once found around the Port Arthur penal colony, but today lives exclusively in Frederick Henry Bay in Tasmania.

How Many Currently Exist

Although the red handfish is historically in Tasmania waters, they have only lived in two reefs in Frederick Henry Bay. Researchers believe there are less than 100 adults of the species alive in the wild today.

Fun Fact

Unique to the handfish genus, this species walks across the ocean floor using their over-sized “hands” rather than swimming like most fish.

4. Devils Hole Pupfish (Cyprinodon Diabolis)

The Devils Hole Pupfish is an endangered species belonging to the pupfish family and is a close relative of the Death Valley pupfish.

Where Are They Found

The Devils Hole pupfish name comes from the region in which they inhabit, Devils Hole.  This cavern is a geological formation located in Nevada, with a small water home to the Devil Hole pupfish.

How Many Currently Exist

Many threats to the Devils Hole pupfish’s natural environment include:

  • Depletion of groundwater
  • Inbreeding depression
  • Changing algae
  • Shifting sediment

Because the Devils Hole pupfish is exclusive to this one location that undergoes threats, it lists as a critically endangered species with 136 mature fish as of 2023.

Fun Fact

The Devils Hole pupfish’s natural habitat is one of the smallest of any vertebrate known worldwide.

5. Adriatic Sturgeon (Acipenser Naccarii)

The Adriatic sturgeon, or Acipenser naccarii, is another one of the rarest fish in the world belonging to the sturgeon family. According to the International Union for Conservation of Nature (IUCN), the Adriatic sturgeon is critically endangered and possibly extinct in the wild.

Where Are They Found

In the wild, the Adriatic sturgeon is native to the Adriatic Sea and large rivers in Albania, Greece, and Italy.

How Many Currently Exist

There is a chance that the Adriatic sturgeon is functionally extinct in the wild. However, through conservation research efforts in microchipping juveniles, there is reason to believe that some do still exist.

Fun Fact

The largest Adriatic sturgeon weighs in at nearly 90 pounds, or 40 kilograms.

6. Tequila Splitfin (Zoogoneticus Tequila)

The Tequila splitfin, or Zoogoneticus tequila, is also known as the Tequila fish and belongs to the goodeid family containing 50 different species.

Where Are They Found

Much like the rest of the genus, the Tequila splitfin is native to Mexico, specifically Tequila Volcano near Jalisco. Today, the rare fish is only exclusively in a spring pool in Teuchitlan, approximately 13 feet in diameter.

How Many Currently Exist

Due to limitations in their natural environment and reduced to a single pool, the Tequila splitfin population is below 50 adults. Although once steadily populating rivers, today it is impossible to find any in this area.

Fun Fact

Researchers once believed the Tequila splitfin was extinct in the wild until discovering the spring pool in Teuchitlan in the early 2000s.

7. Giant Sea Bass (Stereolepis Gigas)

The giant sea bass, or Stereolepis gigas, goes by many common names, including black sea bass and giant black sea bass. Despite these familiar names, the giant sea bass belongs to the wreckfish family, not the sea bass family.

Where Are They Found

You can find the giant sea bass in the northern Pacific Ocean. This rare fish range is from Humboldt Bay in northern California to the Gulf of California in Mexico.

How Many Currently Exist

The giant sea bass was plentiful until the 1950s when overfishing drastically reduced the population to a critically low level. Thankfully, because the California Department of Fish and Game recognized in the late 1970s that the giant sea bass was in danger of facing extinction, they have been able to make a comeback slowly. 

Today there are approximately 500 adults giant sea bass, 40 to 50 spawning annually near Catalina Island.

Fun Fact

Giant sea bass has been recorded up to over eight feet long and weighing over 700 pounds. These giant fish are so large that they have diets that consist of smaller fish and crabs.

8. Kissing Loach (Parabotia Curtus)

The kissing loach, or Parabotia curtis, is known in Japan as the Ayumodoki and belongs to the Botiidae family known for their ray-like fins.

Where Are They Found

The kissing loach is native to the lakes and streams of Honshu in Japan. 

How Many Currently Exist

The kissing loach is on the endangered species list as of 1970. There have not been many conservationist efforts made to save the species, and today there are less than 800 adults in the wild.

Fun Fact

The kissing loach is scavengers that are also omnivorous. As they are bottom feeders, they are not usually picky about what they eat.

9. Smalltooth Sawfish (Pristis Pectinata)

The smalltooth sawfish, or Pristis pectinata, belong to the sawfish family known as carpenter sharks.

Where Are They Found

The smalltooth sawfish is native to the Caribbean and the Gulf of Mexico and prefers tropical and subtropical climates. Historically, these rare fish had ranges spanning from the United States to Uruguay.

How Many Currently Exist

In the United States, where it is the only sawfish that is still alive in the wild, the smalltooth sawfish population makes up less than 5% of its historical population. It has undoubtedly become extinct in the majority of regions it once inhabited.

Fun Fact

October 17th is officially International Sawfish Day to bring awareness and preserve the quickly depleting species.

10. European Sea Sturgeon (Acipenser Sturio)

The European sea sturgeon, or Acipenser sturio, is also known as the Atlantic sturgeon or the common sturgeon and is the largest migratory fish in France’s waters.

Where Are They Found

Although they were once prevalent throughout Europe’s waters, today, they have been found to breed exclusively in France’s Garonne river basin. The species are diadromous, making them able to thrive in freshwater and seawater. 

How Many Currently Exist

Some of the primary threats to the European sea sturgeon population includes:

  • Caviar fishing
  • Waterway construction
  • Pollution

Luckily, there is a large number of European sea sturgeons in captive stock in conservation efforts. Somewhere between 20-750 adult European sea sturgeons are alive in the wild today.

Fun Fact

The European sea sturgeons gained popularity in the 19th century as a result of caviar production. In 1982 the species became protected in France and 1998 in Europe, and efforts have since worked towards rehabilitating the species.

(You might also be interested in reading the Most Expensive Fish)


It’s no secret that humans’ global impact on natural environments can be devastating. Quite possibly, it is exhibited the most in terms of the ocean species. Luckily, through conservation efforts, researches have been able to help slow or eradicate the entire elimination of fish species.

Now that you have taken a look at the 10 rarest fish worldwise, you can better understand what makes them so unique and appreciate their existence, even if it is limited.

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