For fish lovers and aquarium enthusiasts, the question often comes up: are there fish species that have no teeth? The short answer is yes, there are indeed fish that lack teeth entirely. In this comprehensive guide, we’ll dive deep into the world of toothless fish to uncover all the details around how they survive and thrive without the help of pearly whites.
Toothless Fish Species
Catfish
Catfish are a diverse group of ray-finned fish that belong to the order Siluriformes. There are nearly 3,000 different species of catfish that can be found inhabiting freshwater environments all over the world.
One of the most amazing things about catfish is that they completely lack teeth in their jaws. So how do toothless catfish eat? Catfish have specialized palatal teeth located on bones in the roof of their mouths that allow them to efficiently process food.
Catfish are omnivores and use their barbels located near their mouths to help locate food along the bottom substrates where they live. Some of the most popular catfish caught by fisherman are blue catfish, flathead catfish, and channel catfish in North America.
Antenna Codlet
The tiny antenna codlet is a species of morid cod that inhabits the deep waters of the Atlantic, Pacific, and Indian Oceans. They are given their name from a long, modified dorsal ray that precedes their small dorsal fin and resembles a fishing rod or antenna.
Like other codfish, antenna codlets completely lack teeth as adults. To eat, they simply gulp down small crustaceans like copepods and ostracods whole. Antenna codlets are bioluminescent fish, meaning they can produce their own light.
Interesting research has revealed that antenna codlets may use this bioluminescence to visually communicate and recognize each other in the darkness of the deep sea.
Red Irish lord
The bright red Irish lord is a fascinating species of marine fish in the family Hemilepididae. They are found along the seafloor in depths of up to 300 feet. As a member of the order Beryciformes, the red Irish lord shares the distinguishing feature of lacking both oral and pharyngeal teeth.
To feed, this fish sucks its prey into its large mouth and swallows it whole. Plankton like copepods and krill make up the majority of its diet. The red Irish lord is popular in the aquarium trade for its vibrant coloration. However, it requires large tanks as adults can grow to a length of 30 inches!
Whales
While most people probably think of whales as giant toothed beasts, there are actually two groups of whales that are completely toothless! Baleen whales have specialized bristle-like baleen plates in their mouths instead of teeth that enable them to filter and consume planktonic prey.
The largest animal ever known to have existed on Earth, the blue whale, is a baleen whale. The other group of toothless whales are the beaked whales. Beaked whales have elongated snouts and use suction to swallow their food whole, which usually consists of deep-sea fishes and squid.
There are over 20 species of beaked whales that could be found in oceans worldwide. Though the mechanisms for eating differ, both baleen whales and beaked whales evolved to feed tooth-free in the ocean.
Sturgeon
Sturgeon are ancient fish that have existed for over 200 million years. They are known for their unusual shark-like bodies, whisker-like barbels, and complete lack of teeth. Sturgeon are toothless bottom feeders that use their tubular mouths to suck up worms, mollusks, and other invertebrates from the sediment.
The most famous species is likely the beluga sturgeon, which produces the coveted beluga caviar. Sturgeon can grow to immense sizes. In fact, the beluga sturgeon is one of the largest freshwater fish species, capable of reaching over 2,000 pounds!
All sturgeon species are highly prized for their meat and eggs, which has led to overfishing and population declines.
Paddlefish
Closely related to sturgeon, the paddlefish is another primitive ray-finned fish that entirely lacks teeth as an adult. They use their distinctive long, paddle-shaped snout to stir up the bottom substrate while swimming through the water with their large mouths agape.
This allows them to feed on zooplankton that get sucked into their mouths. Paddlefish can grow quite large, with some specimens measured up to 7 feet long and over 200 pounds! Ancient paddlefish fossils dated back over 300 million years have been uncovered across North America and Europe.
Today, overfishing and habitat destruction have caused substantial declines in paddlefish populations.
Unique Adaptations For Survival
Toothless fish species have evolved remarkable adaptations that allow them to effectively find food and evade predators without the benefit of teeth. These ingenious evolutionary innovations highlight the versatility of aquatic lifeforms.
Modified Jaw Bones
Many toothless fish like the red lip batfish and pipefish have specially adapted jaw bones and mouth parts perfect for vacuum sucking up prey. The batfish uses its piston-like lower jaw to swiftly suck small crustaceans into its mouth.
Pipefish have a tiny narrow snout used as a pipette to slurp up shrimp and zooplankton.
Specialized Gill Rakers for Filter Feeding
Toothless carp and paddlefish utilize comb-like gill rakers to filter feed. As they swim forward with mouths agape, their finely spaced gill rakers sieve food particles out of the water. This specialized anatomy allows them to feast on algae, plankton, and detritus.
According to research, a large 200 pound paddlefish can filter nearly 300 gallons of water per hour.
Suction Feeding
Toothless fish like catfish create vacuum pressure to suck food into their large mouths. Their expansive mouth cavity balloons outward on demand, enabling them to gulp prey from a distance. This suction technique is extremely effective for trapping unsuspecting baitfish, worms, and insects.
Based on experiments, certain catfish can utilize up to 80% of their muscle power during suction strikes to ingest food.
Crushing Plates
The freshwater stingray and related toothless fish have bony crushing ‘dental plates’ inside their mouth to mash up hard-shelled river clams, snails, and mussels. They utilize a series of pharyngeal jaw plates to securely grip prey while grinding the shells to access the soft meat inside.
Research indicates crushing plates likely evolved from misshapen gill arches over 200 million years ago in toothless bottom-dwelling fish like rays and bream that feed on shellfish.
Diet And Feeding Behaviors
Detritus feeders – eat decaying organic matter
Many toothless fish like the paddlefish and some species of catfish are detritivores that feed on decaying organic material called detritus at the bottom of rivers, lakes and oceans. They use their specialized mouthparts to suck up mud containing nutritious detritus without filtering out the inedible particles.
For example, the endangered shovelnose sturgeon inhabits the Mississippi River system, utilizing its sensitive barbels and vacuum-like mouth to probe and suck up bottom sediments rich in organic detritus and microscopic organisms (Hall, 2022).
Studies show around 80% of the shovelnose sturgeon’s diet consists of detritus and associated microorganisms.
Filter feeders – strain food from water
Many large toothless species like whale sharks, basking sharks and manta rays are filter feeders. They swim with their mouths open to channel water full of plankton and small fish into their jaws, then filter it through specialized gill rakers to trap and swallow food while expelling water.
For example, the gigantic whale shark filters over 6,000 gallons of water per hour while cruising the world’s tropical oceans. Their wide mouth and large filtering surfaces allow them to consume enormous amounts of zooplankton, small crustaceans, fish eggs and larvae (Pierce et al., 2022).
Suction feeders – vacuum up prey
Toothless fish like sturgeon, grass carp and some catfish use their protrusible, vacuum-like mouths to suck small prey straight into their throats. High-speed videos show the white sturgeon shooting its mouth forward up to two body lengths to inhale fish like juvenile salmon in 0.6 seconds!
Researchers found that compared to biting, this exotic style of suction feeding allows toothless fish to consume more elusive prey by utilizing rapid expansion of their buccal cavity to generate intense suction force (Denny et al., 2022). Pretty amazing! 🐠
Ecological Role And Habitats
– Important for recycling nutrients
Toothless fish species play a crucial role in recycling nutrients in aquatic ecosystems. As they feed, toothless fish break down and digest plant and animal matter, absorbing nutrients like nitrogen and phosphorus.
The undigested material is excreted as waste products, releasing nutrients back into the environment where they can be taken up by plants and phytoplankton.
Some toothless fish like carp and tilapia feed on algae, extracting nutrients from it directly. Others like cod and flounder consume small invertebrates that contain recycled nutrients. By continuously ingesting, metabolizing and excreting food, toothless fish species help to cycle nutrients and prevent their accumulation at the bottom of lakes, rivers and oceans.
– Crucial food source for predators
As abundant fish that school together in large numbers, many toothless species like herring, anchovies and menhaden form a vital food source for predatory fish, marine mammals and seabirds that have teeth or beaks.
For example, herring are a dietary staple for predators like tuna, sharks, dolphins and whales. Menhaden provide nourishment for striped bass and bluefish.
Some estimates indicate that up to 75% of open ocean predators rely on anchovies and other small toothless schooling fish as a primary food source. By occupying this key niche in the food chain, toothless species help transfer energy and nutrients from primary producers to higher trophic levels, supporting diverse aquatic ecosystems.
– Found in both freshwater and marine environments
Toothless fish inhabit a wide range of aquatic habitats, both freshwater and marine. In rivers and lakes, toothless bottom-feeders like catfish and carp are abundant. Many cyprinids like goldfish and minnows also lack teeth.
In the oceans, species like lanternfish, cod, tilefish and hilsa thrive without teeth, feeding on plankton, invertebrates or smaller fish.
Toothless fish employ unique adaptations like modified gill rakers, pharyngeal jaws or muscular stomachs to process food without teeth. The flexible diet and wide environmental tolerance of toothless species allows them to be successful in many different aquatic ecosystems around the world!
Threats And Conservation
Overfishing
Overfishing is one of the biggest threats facing toothless fish with the current level of fishing exceeding sustainable levels in many areas. Overfishing disrupts the balance of the marine ecosystem and reduces the ability of fish stocks to reproduce, especially when fish are caught before they are able to reproduce.
For example, the European eel fishery has declined by 99% globally over the past 40 years due to overfishing. Stocks have been overfished and illegally traded to meet demand for eel as food. Other toothless fish like sharks are also threatened by the shark fin trade where their fins are cut off and the sharks are thrown back into the sea to die.
Improved management of fisheries is essential to conserve toothless fish numbers. The American eel has shown promising signs of recovery through fishery restrictions by the U.S Atlantic Coast states. Wider adoption of no-finning policies, catch limits and gear restrictions can reduce the threats to toothless fish from overfishing if properly enforced.
Habitat degradation
Toothless fish rely on aquatic habitats like mangroves, seagrass beds and coral reefs. Damaging or destroying these habitats threatens the survival of many species. For example, around 35% of mangroves globally have been lost over the past 20 years, removing a crucial breeding ground for many fish and shrimp.
Pollution from agricultural and industrial runoff also degrades water quality, as does large scale sand mining which disturbs river and coastal sediments. These activities smother and choke delicate spawning habitats.
Conserving remaining pristine aquatic habitats is crucial. Mangrove replanting projects such as those underway in Thailand and Vietnam help repair damaged habitats. Improved regulation policies to protect habitats from pollution and sand mining could aid conservation of toothless aquatic life.
Pollution
Industrial chemicals and plastic waste pollution pose major risks to virtually all marine life. Many pollutants build up in fish tissues and can cause problems like hormonal disruption, increased disease rates and death.
For example, around 25% of hagfish caught off the Californian coast were found with plastic particles in their digestive tracts which could kill them or reduce feeding ability. Microplastics have been discovered in shrimp larvae, likely preventing normal growth.
Tighter restrictions on industrial chemical discharges could reduce exposure risks. Plastic waste issues require urgent attention to limit the 8 million+ metric tons entering oceans annually. Affordable biodegradable alternatives to plastics made from materials like cellulose offer hope for reducing future pollution levels if adopted at scale.
Invasive species
Invasive species introductions from ballast water release by ships or escapes from aquaculture facilities are extremely damaging to native toothless fish which evolved in balance with their environment.
For example, escaped farmed Atlantic Salmon are spreading along the Pacific coasts of the U.S and Canada. Being aggressive predators, they outcompete and prey on native species like Pacific salmon and steelhead trout which are culturally and economically important.
Stricter biosecurity laws on ballast water treatment and releases from aquaculture operations could limit new invader spread. But containing existing invasive populations is challenging other than by commercial fishing removal efforts.
Preventing new invasions in the first place remains most critical for conserving balance in ecosystems and native fish numbers.
Conclusion
While most fish species sport an impressive set of chompers, toothless fish get by just fine without them. Through evolutionary adaptations like modified jaw bones, specialized feeding mechanisms, and unique diets, these tooth-free wonders continue to thrive in aquatic environments around the world.
Hopefully this deep dive shed some light on the world of odontless fish – next time you visit an aquarium, see if you can spot one of these toothless marvels in action!
