10 Commonly Found Aquarium Fish That Bite (With Photos)

A fish that can bite

Biting is common among fish, and a few can bite you too.

Some of these bites can be painful and cause severe injuries to you or the other fish.

So, let’s learn about the various aquarium fish that bite.

10 Aquarium Fish That Can Bite

1. Oscars

Oscar fish

Oscars are a species of the Cichlid family native to South America.

They primarily inhabit the slow-moving waters with lots of submerged vegetation, debris, and rocks that provide them enough spots to hide from potential predators.

Since oscars belong to the cichlid family, they’re known for being aggressive and territorial toward other fish.

They display aggression and can bite tankmates if cramped for space due to overcrowding, food scarcity, poor tank conditions, stress, or while defending their territory.

Oscar biting a small fish can be fatal as it can lead to severe injuries.

Hence, it’s crucial to select their tankmates in a community aquarium.

On the other hand, oscars are usually friendly toward humans.

However, they can bite your finger if they’re not used to seeing your finger in the tank.

They feel threatened by it and will try to get rid of it as soon as possible.

The bite, however, is not too hard to tear human skin as they have minuscule teeth.

At the most, the bite may cause minor abrasion to the skin.

Another good thing is you can train these fish not to bite.

For this, you can consider getting a baby oscar as a pet and train it not to bite too hard.

2. Jack Dempsey

Jack Dempsey Cichlid

Jack Dempsey fish are one of the highly aggressive cichlid species.

They have feisty personalities and are known to chase, bite, or bully small or vulnerable fish.

Male Jack Dempsey fish are particularly highly territorial and bite any fish that invade their territory.

These fish also bully and bite to assert their dominance inside the tank.

Besides, they become aggressive during mating and when the living conditions aren’t favorable.

Since Jack Dempsey fish are carnivores, they have sharp teeth and a powerful jaw.

Their bite is so powerful that it can pull a chunk of flesh out of their prey.

These fish can also bite human fingers, knuckles, and the back of the hands.

Their bite is also excruciating and can even leave scars.

3. Bettas


Bettas are also popularly known as Siamese Fighting Fish for their aggression.

However, they’re favorites among aquarists for their flashy fins and attractive colors that brighten up the tank.

Male bettas are naturally aggressive and territorial toward their species.

So two male bettas housed in the same tank will fight and bite each other until one gets severely injured.

Male bettas also become aggressive and bite brightly colored fish or fish having flowing fins and tails.

It’s because bettas look upon other fish that resemble them as a threat.

Bettas can also bite their tankmates when they’re cramped for space, food is scarce, or while establishing their territory.

They’re also highly protective of their eggs. Hence, they bite and nip any fish that approaches their territory.

Besides tankmates, bettas can bite you if you put your hand in the tank.

They may bite out of curiosity or self-defense if they perceive your hand as a threat.

However, their teeth are too small to pierce human skin. Hence, the bite usually won’t inflict severe damage.

4. Tetras

Tetra in an aquarium

Tetras are aquarium fish popular for their lively personalities and vibrant colors.

They primarily inhabit the Amazon river basin in South America.

However, these fish are now found worldwide due to their popularity in the aquarium trade.

Tetras are docile and compatible with most types of fish. However, they’re natural fin-nippers.

Some tetra species like neon tetras, serpae tetras, rosy tetras, black skirt tetras, emperor tetras, white skirt tetras, flame tetras, etc., are known to chase and nip fins of other fish.

Black skirt tetras usually nip fins of slow-moving fish and fish with long flowing fins.

Tetras nip fins, particularly over territorial disputes, food scarcity, and lack of space in the aquarium.

However, you can certainly curb their fin-nipping behavior by keeping them under appropriate conditions.

5. Goldfish


Goldfish is one of the most popular aquarium fish in the world.

They’re attractive, easy to care for, relatively inexpensive, and can withstand various water conditions.

They’re peaceful and compatible with many fish that have similar size and temperament.

However, goldfish can become aggressive and resort to biting if the living conditions aren’t conducive.

Goldfish mainly bite other fish if the tank is overcrowded, food is scarce, they’re defending themselves from bullying fish, they’re sick, or during mating.

Although goldfish can bite their tankmates, they usually don’t bite humans.

They’re playful and can nibble your finger if you put your finger in the tank.

Even if a goldfish bites, you won’t feel much pain as they have small teeth at the back of their mouth.

6. Plecos

Pleco on driftwood

Plecos are freshwater fish that have been around for ages.

They’re found in many habitats, including rivers, lakes, ponds, streams, swamps, and even oceans.

Aquarists also prefer plecos because they’re easy to care for and have the unique ability to clean the tank algae.

These fish are usually peaceful and compatible with many fish that have a similar temperament.

However, they may show aggression at times.

Plecos can bite under stressful conditions.

Stress can occur due to food scarcity, space constraints, unfavorable water parameters, poor water quality, constant bullying, and other factors.

Also, male plecos can’t tolerate each other once they grow up.

Hence, if you house two male adult plecos in the same tank, they will bite and chase each other for dominance and territory.

The fight can continue until one of them gets severely injured.

Plecos also become territorial during breeding. Male plecos are highly protective of their eggs.

They keep their eggs safe from other tankmates and, in the process, can bite or chase away the fish that try to eat their eggs.

7. Guppies

Guppy in a tank

Guppies are the most popular fish due to their attractive colors, small size, low cost, and ease of care.

Due to their docile nature, they’re one of the preferred choices for community aquariums.

However, these little creatures can become aggressive and bite their tankmates.

Guppies can bite when the living conditions aren’t conducive.

They can then become territorial and resort to biting due to poor water conditions, lack of space, overcrowded tank, territorial disputes, food scarcity, incorrect male-to-female ratio, unfavorable water parameters, and incompatible tankmates.

Guppies can also bite when you add a new fish to the tank. They usually try to exert dominance over the newly added fish.

Although guppies can bite their tankmates, they usually don’t bite humans.

They bite humans only when they try to touch them or feed them with their hands instead of dropping food into the tank.

Although guppies occasionally bite humans, the bite isn’t powerful to hurt.

8. Angelfish

Angelfish are among the most desirable fish in the aquarium trade due to their vibrant colors and elegant shapes.

They’re peaceful compared to other cichlid species. However, they can be aggressive and bite other fish if they feel threatened.

This behavior is more likely to happen when the tank is overcrowded, food is scarce, water quality is poor, a pecking order is being created, or when they’re stressed or agitated.

Angelfish also become aggressive during breeding and are fierce while protecting their eggs.

Hence, any fish that comes near their eggs are likely to be chased away or get bitten.

Angelfish are also known to bite humans.

They can bite if you stick your hand in the aquarium to feed them or if you stray too close to their breeding ground.

Either way, there is nothing to worry about as their bites aren’t harmful. In most cases, the bite won’t even hurt.

9. Mollies


Mollies are freshwater fish belonging to the Poeciliidae family.

They’re primarily found in parts of Central America, like Mexico and the southern United States.

Mollies are famous in the aquarium trade due to their hardiness and ability to adapt to various environments.

However, mollies are known to be aggressive toward other fish species.

Despite being friendly and peaceful, they’re notorious for fin-nipping.

They’re known to nip the fins of other fish species with large, delicate, and flowing fins.

Hence, fish such as bettas, angelfish, fancy goldfish, and gouramis should be avoided with mollies to curb their nipping behavior.

Also, male mollies love nipping the fins of other males to establish dominance and defend their territory.

10. Platies


Platies are freshwater fish belonging to the Poeciliidae family. They’re native to South America and Mexico.

These fish are favorites among aquarists for their vibrant coloration and docile nature.

They have a short, flattened body with small pointed teeth.

Platies usually bite other fish to defend or compete for territory.

They also become territorial during mating and bite each other’s fins.

Female platies also become equally aggressive during mating and bite their partner’s fins to have an easier time inseminating them.

Although platies nip fins during mating, they’re not fin-nippers.

The strength of a platy’s bite depends on its size.

The larger the size of the fish, the stronger the bite. However, the bite is usually not strong enough to cause harm.

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