15 Fish With Big Lips (With Photos)

Look at any cartoon or animation of a fish and you’ll notice that it has large lips. While this design is mostly for making the fish seem more human for entertainment, there is a lot of science behind the evolution of fish lips. In fact, the shape, size, and movement of fish lips can tell a lot about the overall habits of the species.

Here are some of the most interesting fish with big lips and how they use them!

Evolution Reasons

Lips might not seem like an important of evolution, but most fish are predators that use their mouths every day to catch prey. This means that the mechanism for catching these prey should be as specialized as possible! At the same time, lips can act as a way to fight off competition or attract mates.

When fish first evolved, they had a simple mouth that lacked a jaw. Today, some of those ancestors can be seen in jawless fish, like lampreys (Hyperoartia class). The development of a skeletal jaw allowed fish to diversify in both prey and lifestyle. Soon, mouth structure gave way to teeth, crushing palates, and suction cup-like structures.

Different Mouths of Fish

When looking at fish with big lips, consider the overall purpose of the mouth structure. A fish with decent-sized lips that preys on organisms in the substrate may not find it beneficial to have an upwards-pointing mouth. Because of this, we see 4 main types of mouths among freshwater and saltwater fish.

1. Terminal mouth. Terminal mouths are commonly seen on most fish, including some of the most popular fish species (like freshwater angelfish) available to a fish enthusiast. A terminal mouth means that the mouth is at the same level as the fish in the front of the head.
2. Inferior mouth. Mostly seen on bottom-dwelling fish species, inferior mouths point down. These mouths are specialized for catching prey underneath the fish.
3. Superior mouth. Opposite to the inferior mouth, the superior mouth points up. This evolution is commonly seen in fish that stay near the surface of the water, like arowana, but can be found in fish at all levels. In some cases, superior mouth fish species use their large mouths as a trap door mechanism which creates a vacuum and quickly pulls prey into their mouth.
4. Protrusible mouth. A protrusible mouth can have any of the previous features on this list, like a fish that has both a terminal and protrusible mouth. A protrusible mouth means that the fish can extend its mouth forward, oftentimes extending their lips in the process. This can be helpful for quick ambush attacks as well as for fighting with other fish.

Why does your fish have big lips and a big mouth?

There are a few reasons why the size and shape of the lips and mouth might vary across species. These are mainly due to predation, interactions, and reproductive purposes.

Predation

Predation is the main reason why fish lips look the way they do. While the mouth is the cavity that holds and processes food, the lips help catch the prey.

One of the most extreme lip adaptations to predation can be seen in parrotfish (Scaridae family) in tropical and subtropical waters around the world. Most species within this scientific community live on coral reefs where algae and coral are abundant. In response, parrotfish evolved hard beaks that can crush, break, and scrape hard surfaces for food.

As mentioned before, the overall orientation of the mouth also aids in predation. In the case of the parrotfish, their mouths are terminal, meaning straightforward. However, fish that live on the bottom of coral reefs, like saltwater blennies (Blenniiformes order), have downward-pointing inferior mouths.

Interactions

Another reason why lips might be the most notable feature of a fish is due to how they interact with one another.

One of the most popular cases of lip-to-lip interaction is from a popular fish, the kissing gourami (Helostoma temminckii). These fish have terminal, protrusible mouths that they use to extend to meet with other kissing gouramis. This lip-to-lip contact might seem romantic, but it’s actually a way that the fish are competing and asserting dominance.

If you notice this happening in your aquarium, it could be a sign that your fish are stressed or that the male-to-female ratio is imbalanced.

Reproductive Purposes

Lastly, big lips can be a way that fish use to attract mates. Reason stands that if predation is successful due to big lips, then the big-lipped fish must have good genes. This makes the fish very desirable to breed with.

However, some fish, like freshwater cichlids, also use their lips and mouths to hold and protect fertilized eggs and fry. Male bettas even use their tiny mouth to create bubble nests and to transfer fertilized eggs to the surface of the water.

Top Fish With Big Lips

Here are some amazing marine creatures with the most obvious facial features!

1. Koi Fish

• Scientific Name: Cyprinus rubrofuscus var. “koi”
• Diet: Omnivorous
• Size: 1-3 feet
• Origin: Japan (domesticated)
• Type: Protrusible mouth
• Available to Hobbyists: Yes

If you’ve ever been to a koi pond, you may have been greeted by many large mouths gasping at the surface of the water for food. Koi fish have reasonably big protrusible mouths for what they eat, which consists of mostly plants, invertebrates, algae, and even fallen fruits that have made their way onto the bottom of the substrate.

A protrusible mouth allows koi to extend their lips to quickly catch prey. These freshwater fish species do not have teeth in their mouth but have pharyngeal teeth towards the back of their mouth which help grind and break up food.

Koi also have barbels around their mouth that can help them navigate and find prey in murky waters.

2. Flowerhorn

• Scientific Name: Hybrid
• Diet: Omnivorous
• Size: 8-16 inches
• Origin: Southeast Asia (domesticated)
• Type: Large mouth, prominent lips
• Available to Hobbyists: Yes

Flowerhorn fish are a hybrid cichlid available in the aquarium hobby. These are very colorful fish with big lips and big personalities.

Flowerhorns are omnivorous fish that will willingly eat plants, insects, and small fish. They have teeth directly in their mouth as well as pharyngeal teeth further back to help process larger foods.

As cichlids, flowerhorn fish can be aggressive. They have been known to lock lips with other fish in an attempt to defend their territory or overtake other males. They often chase fish around the tank and can inflict considerable damage with their large mouth.

3. Grouper

• Scientific Name: Serranidae family
• Diet: Carnivorous
• Size: 35-90 inches
• Origin: Worldwide tropical and temperate oceans
• Type: Protrusible mouth
• Available to Hobbyists: Some

Groupers are some of the largest fish in the marine world, it only makes sense that they have the mouth to match.

Groupers are a large scientific family of fish, with some individuals, like the giant grouper or Queensland grouper (Epinephelus lanceolatus), growing upwards of 7 feet long. These saltwater fish are largely carnivores with strong jaws, preferring to eat large fish and crustaceans. Some species of grouper have teeth in their mouth to catch and devour prey, but most species swallow their prey whole.

Most grouper fish are ambush predators. A protrusible mouth allows them to keep some distance from prey while also guaranteeing a successful hunt.

4. Giant Gourami

• Scientific Name: Osphronemus goramy
• Diet: Omnivorous
• Size: <2 feet
• Origin: Southeast Asia
• Type: Protrusible mouth
• Available to Hobbyists: Yes, though not recommended

The giant gourami fish is another species with a big mouth. These gourami fish should not be confused with the smaller popular aquarium fish, the kissing gourami, which uses its protrusible lips to lock with another fish in competition and defense. This behavior is not seen in giant gourami.

While the giant gourami can also be territorial and aggressive, their mouth is a greater threat to prey. No worries though, as giant gouramis are herbivores that use pharyngeal teeth to grind plants and algae. However, they may sometimes eat smaller fish and invertebrates.

5. Largemouth Bass

• Scientific Name: Micropterus salmoides
• Diet: Carnivorous
• Size: <2.5 feet
• Origin: North America
• Type: Large mouth
• Available to Hobbyists: Yes, though not commercially

The largemouth bass is a popular fish species among anglers, but less commonly seen in the aquarium hobby. These are big game fish that need a carnivorous diet and get very large, which make it difficult to keep in aquariums.

The largemouth bass is typically the apex predator in its freshwater lake and pond ecosystems. These fish are ambush predators that capture their prey by creating a vacuum when they open their mouths. Largemouth bass use teeth in the front of their mouths as well as further back pharyngeal teeth to process their food.

Unfortunately, the largemouth bass is an invasive species in some countries, namely Canada and Japan¹.

6. Lionfish

• Scientific Name: Pterois spp.
• Diet: Carnivorous
• Size: 4-18 inches
• Origin: Worldwide tropical and temperate oceans
• Type: Protrusible mouth
• Available to Hobbyists: Yes

Lionfish are very invasive fish, and their availability as aquarium fish is regularly questioned. These fish have large protrusible mouths lined with sharp teeth to catch smaller fish and invertebrates. They may even eat other lionfish.

While hunting, lionfish will confuse their prey with jets of water until they attack. They also have specialized swim bladder muscles that help provide calculated movement for a guaranteed kill.

7. Gulper Catfish

• Scientific Name: Asterophysus batrachus
• Diet: Carnivorous
• Size: <1 foot
• Origin: South America
• Type: Inferior mouth
• Available to Hobbyists: Yes

The gulper catfish (video source), also known as the ogre catfish, is a medium-sized catfish capable of preying on fish the same size as itself. Like many other catfish species, the gulper catfish has an inferior mouth that is on the bottom of its head and pointed downwards to prey on substrate-dwelling organisms.

While the gulper catfish will generally eat whatever it finds, it uses its large mouth to strike other fish by the head. The gulper’s mouth is lined with small sharp teeth that make it almost impossible for prey to escape its hold. Then, the catfish continues to swallow its prey whole, often stretching and distending the stomach. It is well known for eating fish larger than itself!

8. Stonefish

• Scientific Name: Synanceia spp.
• Diet: Carnivorous
• Size: 14-20 inches
• Origin: Indo-Pacific (Indian Ocean)
• Type: Superior and protrusible mouth
• Available to Hobbyists: Rarely

Stonefish, a type of scorpionfish, are the most venomous fish known. These fish have deadly stings that keep them safe from predators. However, they are also adept predators with modified mouths.

As bottom-dwellers, stonefish have superior mouths that point upwards toward prey. They also have protrusible mouths that quickly open and create suction to help complete an undetected ambush. They lack teeth but have a bony palate that can easily crush prey.

9. Sarcastic Fringehead

• Scientific Name: Neoclinus blanchardi
• Diet: Carnivorous
• Size: <1 foot
• Origin: Pacific Ocean
• Type: Large and distended mouth
• Available to Hobbyists: No

Big lips are important to the sarcastic fringehead. These fish have very unique lips with a large mouth to go along with them.

When open, a sarcastic fringehead’s mouth forms a rounded pentagon with bright colors along the edges. This large mouth is often used to fend off other males and competitors through mouth wrestling and gaping displays. This is a necessary behavior as these fish inhabit coral reefs and have very specific territories around caves and tight spaces.

10. Arowana

• Scientific Name:Osteoglossidae family
• Diet: Carnivorous
• Size: 2-3 feet
• Origin: South America, Southeast Asia, and Australia
• Type: Upturned and protrusible mouth
• Available to Hobbyists: Yes

A lot can be deducted from looking at an arowana’s mouth. These freshwater fish are almost always seen in surface waters. This, in addition to their large and upturned mouth, shows that their diet consists of both aquatic and land animals, like smaller fish, insects, and even birds. In fact, these fish are capable of jumping considerable heights out of the water.

Arowana also have sensory barbels that help them detect prey along with teeth that keep prey in their mouth.

11. Oscars

• Scientific Name: Astronotus ocellatus
• Diet: Omnivorous
• Size: <1.5 feet
• Origin: South America
• Type: Protrusible mouth
• Available to Hobbyists: Yes

Oscars are the number one tropical freshwater fish for eating things they aren’t supposed to. These fish are very curious and very hungry and won’t hesitate to try eating something that isn’t food in their tank.

In the wild, these fish are just as eager to eat other fish, plants, insects, and other food-shaped items. This means that they need a large mouth with a protrusible jaw and teeth to capture prey. Oscars have great natural camouflage, which allows them to wait for their prey to come to them and then ambush attack.

12. Red Shoulder Peacock Cichlid

• Scientific Name: Aulonocara stuartgranti
• Diet: Omnivorous
• Size: <1.5 feet
• Origin: Lake Malawi
• Type: Protrusible mouth
• Available to Hobbyists: Yes

These tropical freshwater fish (video source) use their mouth a lot! The red shoulder peacock cichlid is a benthophagous fish species. This means that they find their food in and around the substrate by taking mouthfuls of it and sifting through for small organisms; they actively hunt for small invertebrates on top of the substrate as well.

In addition, red shoulder peacock cichlids are mouthbrooders, which means they raise their fry within their mouths. These African Cichlids are also naturally aggressive fish, which could lead to locking lips or gaping their mouths to warn off predators and potential competition.

13. Napoleon Wrasse

• Scientific Name: Cheilinus undulatus
• Diet: Omnivorous
• Size: 3.0-6.5 feet
• Origin: Indian and Pacific Oceans
• Type: Protrusible mouth
• Available to Hobbyists: No

Also known as the humphead wrasse, the Napoleon wrasse is undoubtedly a fish with big lips and a big head! These marine fish can be found foraging for food in and around coral reefs. While primarily carnivores, they may graze on algae and seaweed.

It is believed that part of the reason Napoleon fish have such big lips is for attracting mates; large lips indicate better fitness and a more desirable mate.

Unfortunately, Humphead wrasses are endangered due to overconsumption, habitat loss and destruction, and lack of species management.

14. Big Lip Damselfish

• Scientific Name: Cheiloprion labiatus
• Diet: Herbivorous
• Size: 2.5 inches
• Origin: Indo-Pacific
• Type: Big lips and protrusible mouth
• Available to Hobbyists: No

Not all damselfish are created equal. For some reason, the big lip damselfish (video source) has evolved, especially large lips. But why?

Unlike other damsels, the big lip damsel is primarily a herbivore. Their diet consists largely of coral, algae, and other flora growing on rocks around reefs in tropical waters. It is believed that these lips help the fish scrape fleshy coral and algae off hard surfaces. They are commonly seen during scuba diving expeditions.

15. Sweetlips

• Scientific Name: Plectorhinchus spp.
• Diet: Carnivorous
• Size: <2 feet
• Origin: Worldwide tropical and temperate oceans
• Type: Protrusible mouth
• Available to Hobbyists: Yes

Contrary to their name, sweetlips fish (video source) are predators with a big mouth. These saltwater fish likely get their name from their large, and often colorful, pouting lips. However, this mouth is used for catching small invertebrates and fish; caution is needed when keeping them in a home aquarium fish setting.

Some sweetlips commonly kept by aquarium enthusiasts are:

• Harlequin sweetlips (Plectorhinchus chaetodonoides)
• Striped sweetlips (Plectorhinchus diagrammus)
• Oriental sweetlips (Plectorhinchus vittatus)

FAQs

Closing Thoughts

From small fish to big fish, every species has unique lips and mouth. Some are pointed upwards and others down, while some are lined with sharp teeth while others are designed to crush. Most popular aquarium fish have a terminal mouth that is relative to their body size, but others need special dietary and habitat considerations.

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Mark Valderrama

I’m thrilled that you found Aquarium Store Depot! Here you’ll find information on fish, aquariums, and all things aquatics related. I’m a hobbyist (being doing this since I was 11) and here to help other hobbyists thrive with their aquariums! I adhere to a high quality Editorial Process and Review products with real life field usage and practical analysis.

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