Skip to content

101 Facts About Betta Fish Anatomy You Should Know

betta fish anatomy

Betta fish, or the Japanese fighting fish, is a magnificent creature with dazzling and shimmering colors and an enthusiastic personality. As a betta fish owner, it is the duty of the betta fish owner to know all about their fish, their personality, habits, diseases, treatments, tank conditions, and overall betta fish anatomy.

Knowing your betta fish anatomy indicates a responsible and loving caretaker. Like humans evolved and developed specific evolutionary adaptations, betta fish has gone through the same. Bettas are a type of fighter fish endemic to Southeast Asia, where they are known as Siamese fighting fish. Bettas are categorized as Gourami species notable for their vibrant colors and intricate fin formations. The majority of its visible body composition is made up of fins. Understanding the betta fish anatomy can only help you better understand betta fish ailments, remedies, and symptoms, and you will be able to give a healthy life to your Betta. As a result, in today’s post, we hope to provide you with as much information about betta fish anatomy.

External Betta Fish Anatomy:

External betta fish anatomy refers to what we see on its exterior. It includes their eyes, mouth, nose, fins, scales, tail, gills, and any other visible organ of your Betta.

Mouth And Teeth

Mouth And Teeth

You might well have observed that a betta fish’s mouth is inverted upwards, which enables it to capture food on the water’s surface and breathe oxygen simultaneously. Betta fish have a lot of microscopic, pointy teeth on their bottom jaw within their mouth to assist chew apart food before digestion. It’s also why betta fish has a cocky and irritated expression on their faces.

Males assist during mating by sucking the female’s eggs into their mouths, protecting them, and keeping them warm in a region where their teeth have only millimeters to spare. He will then regurgitate them into the bubble nest, where they will be lodged and fertilized. Their teeth have strength more than that of a white shark when measured proportionally to their size.


betta eyes

On each half of their heads, betta fish have two projecting eyes. Their iris is black, which you will see if you look closely. Bettas have excellent vision, as evidenced by their ability to recognize their masters and their agitation when confronted with their projections in an aquarium. They see everything in full color, and they don’t have eyelids or the capacity to blink.

Betta fish are myopic, and their keen sight is only functional up to a radius of 12-14 inches. Monocular vision is the term used to describe the vision of a betta fish. This indicates that their eyeballs are on opposing sides of their heads, and each produces a separate image. Rapid fluctuations in brightness are challenging for their eyes to adjust to.


betta cool fins

A fish’s fins help it navigate around in the water, stay upright, and maintain balance. Bettas have a variety of fins, each with its function. The pelvic fins are also known as the ventral fins and are employed for rowing. Females have a much lesser length than their men equivalents.

Betta employs their dorsal fin, which is placed on top of their body and can differ in form and size, to travel in a straight path. The pectoral fins, sometimes known as Betta’s ears because of their wiggly appearance, are continually in action and help lead a betta through the water.


The outer fish scales, or armor, are found on the body, which can reach a length of more than 6-7 centimeters. A thriving betta fish will have firm scales and brilliant color in confinement. These scales protect it and help it swim. Sensitive aquarium materials and contact with other violent fish can cause injuries to the body.

A mucous outer layer on the top of the fins provides further defense, helping to keep infections and parasites at bay. When your Betta is stressed or anxious, you might notice horizontal lines on its body, specifically females.

Internal Betta Fish Anatomy:

The internal betta fish anatomy consists of anything peculiar to betta fish but is not visible. This is the internal betta fish anatomy and consists of your Betta’s gills, breathing patterns, and swimming designs.

Gills And Breathing

Even though gills are usually visible on the exterior of your Betta, we consider them internal because of the significant role it plays in the internal betta fish anatomy of breathing. Betta fish have gills that permit them to collect oxygen from the tank water or the ocean they live in. Bettas can also flourish in minimal oxygen situations due to their unique system of labyrinth organs.

Bettas use these organs for breathing air from the surface. It is unquestionably helpful to have both in less oxygenated water settings in the wild. Your Betta may nap underwater, presumably using their gills for oxygenation or on the surface level, allowing them to take breaths through surface agitation conveniently.

Like all other fish, Betta fish take in water via their gills. The inside surfaces of the gills capture and eliminate the incorporated oxygen in the water as the water passes through. After that, oxygen is injected into the system via blood and the whole body. 

Swim Bladder

The swim bladder, positioned along the backbone in the back of the body, expands as a betta fish matures. It resembles an inflated bubble and is used by betta fish to adjust their balance and depths in the water. This is performed by controlling the flow of air within it. They’d be swimming on their sides or at the bottom of their tank if they didn’t have this organ.


The guts of a betta fish are about the diameter of its eye. The digestive system breaks down food in the tummy and digests it before passing it into the intestine. Nutrients such as protein and vitamins are ingested and utilized in the form of energy. Please don’t overfeed your fish, as this can lead to swim bladder problems.

Along with this, your Betta has all the other common internal organs, like the liver, kidney, bladder, testes in the case of males, and heart.

Frequently Asked Questions (FAQs):

Do betta fish have brains?

Research suggests they have a brain that helps them strategize and cooperate when betta fish are fighting. On top of that, they recognize their owners, flare up, get hungry, anxious, which indicates the presence of the central nervous system.

Where do bettas poop from?

Betta fish have an anus, too, along with other internal organs, which are behind their anal fins. Their excretes are small in size. Therefore they might not be visible until it piles up.

How big is a betta fish stomach?

A betta fish’s stomach is the same size as its eye. It is small in size. Hence overfeeding can lead to major digestive and swimming issues in your Betta.

Final Thoughts:

This is what we have to say about betta fish anatomy. Betta fish anatomy tells you a lot about the unique characteristics of your pet and can help you know your Betta even more. Knowing about betta fish anatomy also distinguishes between a male and a female betta.