Why Does My Neon Tetra Have a Big Belly? 7 Possible Reasons

A neon tetra can show a big belly if it’s carrying eggs (female fish) or overeating due to overfeeding. The reason could also be a health issue such as suffering from a parasitic infection, being constipated, dealing with physical trauma, suffering from swim bladder disease, or ingesting too much garlic.

Below, we’re discussing each cause and what you can do about it. Let’s get started!

Why Does My Neon Tetra Have a Big Belly?

Here’s a breakdown of the most common reasons behind a neon tetra showing an enlarged belly:

1. It’s Carrying Eggs

Female neon tetras carry eggs until they’re fully developed and ready for fertilization. At this point, the female will lay their eggs at the bottom of the tank and the male will take over the fertilization process.

If a female neon tetra is carrying eggs, its belly will look a lot larger than normal as it expands to accommodate the hundreds of eggs it can produce at a time.

You can detect a neon tetra that’s carrying eggs by observing its behavior. It’ll slow down a bot and stay away from male fish.

Also, you can anticipate the change in the appearance of a female neon tetra by noticing courting behavior in the tank. As a mating invitation, males will exhibit unusual actions such as twitching back and forth and swimming in a square-like pattern.

Neon Tetra on Rocks

2. You’re Overfeeding

If you’re putting too much fish food for your neon tetras, chances are they’ll eat as much as you give. As a result, they’ll be eating more than they need and their digestive processes won’t be able to keep up.

This will lead to fat build-up in the belly area, making the neon tetras look abnormally swollen. In this case, you should stop feeding for a day or two and then continue using a proper amount.

3. It’s Suffering From a Parasitic Infection

If a neon tetra gets infected by a parasite, it’s likely to look bloated with a bigger belly than normal. This is mainly due to inflammation and edema (accumulation of fluid) caused by the presence of the parasite in the fish’s bloodstream.

Neon tetras are prone to parasitic infections if they live in poor water conditions or come across other infected fish. If you suspect such an illness, you should take your fish to a vet as soon as possible.

4. It’s Suffering From Constipation

A neon tetra with a big belly could be suffering from constipation. This is pretty common among new owners who unknowingly give their neon tetras fish food that’s not suitable for their digestive system.

As a result, the neon tetra is unable to properly digest the food and the delay in releasing the products of digestion leads to bloating and constipation. Just like this can a human’s tummy appear bigger, the same happens in neon tetras.

Aside from bloating, you can tell that your neon tetra is constipated by observing its swimming pattern. If it turns erratic, then something is wrong. Additionally, your neon tetra may lose its appetite due to constipation.

To help relieve your neon tetra, give it small bits of daphnia, brine shrimp, or another live food loaded with fiber as it aids in digestion.

You can also prevent it from happening again by looking up fish food made specifically for neon tetra. However, don’t expect to see the big belly appearance go away until the fish manages to pass the food it already ate.

5. It’s Dealing With a Physical Trauma

Another reason your neon tetra could be showing a bigger belly than normal is physical trauma.

If your fish sustained an injury on its abdomen due to crashing into an object in the tank or getting hit by another fish, it can look like it’s bloated.

At the site of the trauma, the fish’s body takes in gas bubbles. This results in enlargement of the neon tetra’s belly. The bloated appearance will remain unless the fish has an easy way to release the entrapped gas.

If you notice swelling, look for a visible cut or injury and treat it right away to prevent further health complications.

Faltasian [CC BY 4.0]

6. It’s Suffering From Swim Bladder Disease

Inside a neon tetra’s abdomen, there’s a small organ known as a swim bladder. It’s responsible for regulating buoyancy and balance in the water.

If the swim bladder gets inflamed, the neon tetra will show a big belly as a symptom. It also won’t be able to swim properly.

Don’t worry though, this disease is relatively easy to treat using medicines readily available in most fish stores.

7. It’s Eating Too Much Garlic

Neon tetras enjoy gulping down garlic, just like many other types of fish do. They can pick up the strong scent of garlic as it spreads through water and attracts them to the source.

Incorporating garlic in fish food can significantly boost growth in your neon tetras as well as promote antioxidant activity and reduce mortality. However, as beneficial as garlic can be for neon tetras, eating too much can have the opposite effect on their health.

Consuming excessive amounts of garlic is very likely to lead to bloating in neon tetras, which makes their bellies look bigger than normal.

Additionally, too much garlic can cause irritation in the neon tetra’s digestive tract, which results in more build-up of gas and an ever more severe case of bloating.

If your neon tetras’ diet features garlic and you notice that the fish are demonstrating bigger bellies than usual, then we’d recommend switching to garlic-free fish food or giving your neon tetras an Epsom salt bath to alleviate the swelling in the abdomen region.

Wrap Up

If your neon tetra is showing a bigger belly than normal, it could be carrying eggs if it’s a female fish or overeating because you’re overfeeding.

If neither reason is the culprit, then the issue could be health-related such as suffering from a parasitic infection, being constipated, dealing with physical trauma, suffering from swim bladder disease, or ingesting too much garlic.