Why Is My Puffer Fish Not Eating? 7 Reasons Explained

WHY is my puffer fish not eating? 7 reasons explained

Pufferfish are very lovely, funny, and colorful saltwater aquarium fish.

They are nice fish and are very good for the community tank. Although they could become aggressive and territorial when they want to.

There are many species of Pufferfish and they all vary in sizes, shapes, colors, and behaviors too.

Despite that they are hardy fish and beginner-friendly fish, sometimes some problems might creep up which might kill them and get you devastated, one of those problems which we will discuss in this article is the inability of your pufferfish to eat.

Pufferfish are very friendly fish and could even be patted on the head by their regular feeder, mainly because they love foods and they are voracious eaters, so once they stop eating, you will know that something is wrong with them.

There are many factors that could make your Puffer stop eating, and we will explain all of them in this article, so read to the end.

Why Is My Puffer Fish Not Eating?

There are many reasons why your Puffer could stop eating and they are:

1. It is new to the environment: Many people don’t know nor understand this, but it is one of the reasons their fish could lose appetite for food.

When you order your fish either from a pet store, online store or even from a friend, that fish will be stressed in the process of transporting it to you either due to the small size of the container it is kept in or the continuous movement of the water it is in due to the movement of the car, bicycle, etc.

When it finally arrives, you are expected to acclimate it first so that it could get used to the new environment it is about to enter, and that will save you a lot of problems such as loss of appetite.

Apart from getting very stressed during transportation, a fish will be shocked being put in new water that is not totally or exactly like the previous water parameters, Temperature, pH, etc it is used to.

Although we tend to overlook all these and call them little things, but to those fish, it is not and it could affect them negatively which could result in some health issues like the refusal to eat anything.

2. There could be a wound in its mouth: Although many people don’t know this, but sometimes a fish could have a wound in the mouth which could be painful when eating and so, the fish could totally refuse to eat.

There are many ways a fish could get its mouth wounded such as the kind of food it eats, trying to eat rocks, maybe eating algae on the rock or any sharp objects in its tank, etc.

Once you find out that your pufferfish is refusing to eat just because its mouth is wounded, it is preferable to seek the advice of a vet other than resort to self-medication which could kill your fish.

3. Poor Quality Food: The type of foods you give your fish will determine how healthy they will be.

Despite that Pufferfish are Omnivores, it means that they are both Carnivores and Herbivores at the same time and could eat almost anything other fish could eat, be it meat, plants, vegetables, and even manufactured foods such as Pellets, etc.

Not all food is healthy for them.

If yours is refusing to eat, it could be that it doesn’t like the food, maybe the food is expired, too big for it to take on or its teeth is just too big to allow it to eat effectively.

Many people don’t even know that Puffers could develop big front teeth due to the kind of diets they are exposed to, and it could hinder them from eating effectively.

So, check the size of the food and crush them if they are big, and buy quality foods for them such as pellets.

Again despite the that they could eat anything, they are more carnivores than herbivores, so they prefer animals such as Snails, Grasshoppers, Blood worms, and any other type of worm, crustaceans such as Brine shrimps, etc.

The point here is to get them a live animal so that they could easily spot the animal moving and go for it.

4. Wrong Temperature: Despite being marine fish, they are tropical fish and do not survive much in cold water temperatures.

Their ideal water temperature is 74 – 78°F and so, so they shouldn’t be kept without a heater that will be regulating the Temperature of the water.

One of the mistakes people make is hoping on their room temperature and leaving their tropical fish at the mercy of fluctuating water temperature which could easily stress your fish.

When the water temperature becomes too cold for the fish, all the organs in their body might start malfunctioning which could reduce the appetite of such fish, so this could be why your Pufferfish is not eating.

Invest in an aquarium heater.

5. Constipation: If your Puffer stops eating all of a sudden, then it could be as a result of constipation.

When a fish is constipated it means that something is blocking its esophagus or intestines.

As we have learned, these fish are pigs when it comes to food, meaning that they could eat anything including some rubbish, maybe by mistake.

For instance, if it eats stone by mistake, which we all know won’t digest, it could cause constipation, and if not treated on time could cause starvation and death.

If you are sure that it swallowed something big, then call the attention of a veterinarian doctor.

If the object is big, the esophagus or the body will bloat. This is why it is not recommendable to keep small stones and gravel that could easily fit into your fish’s mouth.

6. The Presence of Toxins in the Water: Toxins are bad for any aquatic animal, be it fish, crustaceans, Snails, etc, and this could be the reason why your Pufferfish is refusing to eat.

These harmful chemicals such as ammonia, nitrite, chlorine, nitrate, copper, etc could breed in water as a result of dirt, and water sources.

As a fish keeper, you must invest in both Filter and Water testing kits so that you will have to test your aquarium water always and be able to detect any toxin before it devastates your fish’s health.

This is why it is advisable to always change your aquarium water at least once a week and also make sure that the aquarium is always clean, and always test the water before putting it in your aquarium.

7. Illness/ Diseases: Despite being hardy, they could also get sick which might prevent them from eating.

There are many diseases and parasites that could infect them and make them suffer, including losing their appetites such as fin rot, bloat, and the rest.

The fact is, no fish or any other animal will eat or at least eat like they used to eat when they are sick, so the best advice is to get a veterinarian doctor once you notice that your pufferfish is sick and not eating.

How Do I Get My Puffer Fish To Eat?

After reading some of the commonest reasons why your Pufferfish could stop eating, the next thing you will have in mind is “how to get it to eat. well, I have you covered.

Before knowing how to make your Puffer eat, first find out why it is refusing to eat.

Generally, to get these fish to eat, give them what they love most which are meat or smaller animals such as crustaceans, Snails, Worms, krill, etc.

You must give them more meat than any other food because they love meat more.

How Long Can Puffer Fish Go Without Eating?

If your Puffer has stopped eating and you are worried and wondering how long they could stay that way, well I also got your back on this.

On average a Pufferfish could stay up to 5 to 7 days without eating.

The truth is that fish don’t die easily as a result of hunger because they could last very long without food.

Although how long a Pufferfish could last depends on how healthy the fish is, its size, and how it was previously fed.

Smaller or weak Puffer fish won’t last up to a week without food, while big and healthy ones could even last beyond a week and still be alive and active.


It is very important to discover the reason or reasons why your Pufferfish is refusing to eat and deal with it accordingly.


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