Why Is My Lionfish Not Eating? 6 reasons explained and possible solutions

Why is my Lionfish not eating?

Is your Lionfish not eating? are you confused and panicking thinking that something is wrong with your Lionfish because it is refusing to eat? Then this article is for you.

Lionfish are saltwater fish with many species.

They are carnivores because they only rely on eating other animals including their kind.

They are predators and will eat anything that could enter their mouths, and they are voracious eaters.

You will agree with me that once greedy eaters like lionfish stop Eating, then there are reasons for that.

In this article, you will learn all about why these fish could stop eating or go on a hunger strike, as you may call it.

Why Would A Lionfish Stop Eating?

A Lionfish could stop eating if it is sick or constipated.

As I said, there are many reasons why they could lose their appetites for food and the above are just a few of them. You will learn all in this article and many more, so read to the end.

Your Lionfish could stop eating because of the following reasons:

1. It is Constipated: Constipation sometimes known as bloat happens when something blocks a fish’s esophagus or stomach, thereby preventing the fish from eating.

Constipation can happen to any animal, especially aquatic animals like fish which Lionfish fall into.

There are many reasons why a fish could be constipated such as swallowing a Stone, gravel, or any hard object that cannot be digested by the body.

This is not very rare as many Aquarists suffer from this.

We all know that all fish are greedy when it comes to food and they could eat anything that could fit into their mouths.

So, your Lionfish could be constipated and that is why it is refusing to eat anything more.

Constipation could be fatal if nothing is done about it. There is a saying, ” prevention is better than cure” so, prevent your fish from getting constipated.

To prevent this from ever happening, avoid keeping gravel and any other hard object that could easily fit in your fish’s mouth.

Avoid overfeeding them because overfeeding could cause this.

Although if the cause of the constipation is overfeeding, then you have nothing to worry about, just starve them for a day so that they could defecate all they have taken.

2. Feeding them with one particular food: This could cause your Lionfish to refuse to eat.

Many hobbyists are very fond of feeding their fish only one type of food continuously.

Well, there is nothing wrong with it, but sometimes it could become a problem.

For instance, if your fish get used to a particular food, it won’t take anything else as food, so it might ignore any other thing you will try to feed it.

In the case of lionfish, they could sometimes get tired of a particular food and will pay less attention to it.

Imagine giving your’s krill continuously, it will eventually get tired of it and look away whenever you try to feed it with krill.

Too much krill may cause lockjaw in your Lionfish. Try stick feeding, a variety of live foods, or soak frozen and freeze-dried food in garlic to ignite its appetite.

What am trying to say is, if yours is refusing to eat, you might have to change food for it and see what happens. I suggest living Guppy fish.

Hold the food at the tail and lower it into the water, it will try to swim away, thereby drawing the attention of the Lionfish to come and eat it.

3. Wrong water parameters and Temperature: We all know that every fish has its ideal water parameters and Temperature and when they are not kept in such conditions, problems might arise.

Lionfish are tropical marine fish, they dwell in a water temperature of 70 to 78°F.

If the water temperature is below 60, then they might have their organs slowed down which is very likely to affect their appetites.

So, get yours a heater to provide their ideal water temperature.

Wrong water parameters mean that your fish is not in the water that contains its ideal water chemistry.

For instance, breeding of toxins such as Ammonia, Nitrite, Chlorine, and many more through dirt in the water such as poop and decayed organisms could be harmful to your fish and we all know that sick animals don’t eat or eat very well.

The ideal water parameters for these fish are Salinity: 1.020-1.026 pH: 8.1 and 8.4

4. Diseases and Parasites: Lionfish are hardy fish, but that doesn’t mean that they are totally immune to diseases and Parasites.

There are many diseases and Parasites that could infect them and cause them to become sick and stop eating.

Diseases like Fin rot, White spot, bloat, and many more could do this, and some of their signs are swimming erratically, breathing heavily, cloudy eyes, etc.

My only advice for you on this is to seek the attention of a veterinarian doctor.

5. Unsuitable Food: Sometimes the type of food you are giving to your Lionfish could be unsuitable for it.

Despite that, they eat like pigs, and they could be picky sometimes.

We all know that these fish could only eat any food that could fit into their mouths, so giving them bigger animals could be intimidating to them, thereby making them refuse to eat.

Size of food matters a lot, so make sure you only feed them with smaller animals so that they don’t get intimidated and shy away.

6. Your Fish may be new to your tank: It could be refusing to eat because it is new to the aquarium.

Generally, fish will refuse to eat and will sometimes go into hiding if they are new in an environment.

This mainly happens as a result of a lack of acclimation and stress.

I strongly recommend acclimating your fish before keeping them in your fish tank because it will solve a lot of future problems for you.

Acclimation is the process of making fish and other aquatic animals get used to an environment where they will be Kept.

To acclimate your fish, once it arrives from the pet shot in a nylon bag, take that bag and place it on top of your Aquarium water and be opening it a little by little so that the aquarium water will mix with that of the one it came within the bag.

This process could take up to 20 to 30 minutes to complete, then fully release the fish into the tank.

Many hobbyists ignore this because they think it is irrelevant, but it is not and lack of it could cause stress and some health issues to your fish.

Do Lionfish Stop Eating?

Lionfish do not stop eating unless it is sick, dislike the food or it is new to the environment.

These fish are pigs when it comes to food, so they don’t just stop eating without a tangible cause.

Can Lionfish Go Without Food For A Week?

Yes, Lionfish could go up to 3 months without food. When there is a scarcity of food, their metabolism slows down and adapts to the condition.

This will make them go on for a very long time without eating and still be very okay and active.

So, Lionfish could stay more than a week without food.

Note – I don’t in any way advocate starving your pet fish.

How Often Should Lionfish Eat?

It is recommendable to feed Lionfish once or twice a day.

It is not as if anything will happen to them if you skip a day or two without feeding them, but for the best result from your fish, feed them at least once with quality foods.

The only time I recommend skipping a day or two without feeding them is when they because constipated as a result of overfeeding so that they could poop out all they have eaten and be free.

How To Feed Lionfish

Feeding these fish could be tricky, this is because sometimes they could not see their food all by themselves, especially those tiny foods and sometimes they will feel too lazy to hunt or they are sick.

To feed them, it is either you take the food ( fish) on the tail or put the whole body inside the water.

The fish will be struggling to swim. away, thereby attracting the attention of the predator fish.

Another method is to tie the food on a rope or hold with any object capable of holding it and place it in the water.

If your predator fish is healthy and active, just put the food in the tank and it will hunt the food all by itself.


These are the reasons why your Lionfish could be refusing to eat. Find out the main reason why it is behaving in such manners and deal with it accordingly, as I explained above.

If things get complicated for you, please reach out to a Vet for possible advice and medication.


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