Why Is My Blenny Not Eating? 6 reasons explained

Why is my Blenny not eating?

Is your Blenny fish not eating? or it stopped eating and you are worried and also you are wondering why such is happening? then read this article to the end. Blennies are saltwater fish, they are very active fish and could eat a lot of algae, especially the lawnmower Blennies. There are many types and colors of Blennies and each has its specific size, lifespan, color, and behavior too. If your Blenny is having problems with eating, here are the possible reasons and the possible solutions.

Why is my Blenny not eating? Blennies could stop eating if they are new in an environment and if they are suffering from diseases.

Blennies are active saltwater fish, although depending on the particular specie, they are omnivores meaning that they are both carnivores and herbivores and could eat both meat and plants.

They are more herbivores than carnivores because they eat more plants and vegetables than meat, for instance, Lawnmower Blennies are often called algae Blenny.

Just like every other fish, they are scavengers and would eat anything edible that could enter their mouth.

It is worrisome and not normal seeing a scavenging fish like them stop eating all of a sudden, it means that there is something wrong with them and we will explain them in a short while.

Why Is My Blenny Fish Not Eating?

Some factors that could make them stop eating all of a sudden are:

1. They are new to the environment: I discovered something unique about many complaints from people that their Blennies are not eating.

I discover that more than half of the people that give this complain, their fish is always new or they just transferred them from their former tank to a new one.

One thing many people don’t understand is that transferring fish and many other aquatic animals could be very stressful and toll taking on them and could even make them sick if precautions are not taken.

The fact is if you just ordered your fish from a fish shop and it arrives in a nylon bag, the fish must be down physically and emotionally through stress and being in a tiny space for a long time and many mistakes people make is to put the fish into a tank at once, no! that’s a costly mistake.

Although Blennies are hardy fish and this mistake doesn’t always kill them, I doubt if much other fish could survive it.

So, once your fish arrives, what you need to do is to acclimate the fish at least for 30 minutes or more by putting the bag it came with on top of the tank water and be opening the bag little by little so that the tank water where you will keep them will be mixing with the water it came with.

The purpose of this is to make them get used to the new environment or water so that they don’t get shocked when placed in such water, which could alter their body system and could make them sick and stop eating or becoming active.

2. Cold Water Temperature: Being kept at a cold temperature is one of the reasons why your Blenny fish could stop eating all of a sudden.

Every living thing has its specific temperature which when altered, the animal might be exposed to some serious health issues.

The ideal water temperature for Blennies is 72-78 °F, this means that they are warm or tropical fish and doesn’t last so long in very cold temperature.

The only solution to this is to buy and keep a heater for them to maintain their ideal water temperature.

3. Presence of Toxins: Toxins are very harmful to aquatic animals and could even kill them if nothing is done about it.

Some of the dangerous toxins are Ammonia, Nitrite, Chlorine, Copper, etc.

These could be caused or bred by dirt such as decayed organisms in the water like poops, urines, dead animals, etc.

Other things that could cause these harmful chemicals are uncycled tanks, bad or contaminated water sources, etc.

As a fish keeper you are not yet serious if you don’t have water testing kits and filters, so buy them and test your water every week also keep the water clean by putting in place a filter that will get rid of some dirt.

The fact is some of these toxins could alter the overall health of your fish which could result in many health issues such as erratic swimming, loss of appetite and even death, and many more.

So, once you notice that these chemicals exist in your fish tank by testing your water through API water testing kits, then do at least 50% water change until the toxins are obliterated.

When it comes to dirt such as poops, etc a filter will help on this.

4. Bad Source: Sometimes this could happen not because the fault is from you, but because you got your fish from a bad source.

The source of your fish contributes so much to how healthy your fish will be, for instance, if the fish was exposed to some cruel treatments in the fish shop, there is every chance that it might suffer from poor health.

Although you might not notice this then, maybe later when they are already in your tank.

My humble recommendation for this is simply to get in touch with a veterinarian doctor for possible diagnosis and medication.

5. Keeping diseased animal with your Blenny: Another reason why your Blenny may be refusing to eat anything could be that it is sick as a result of keeping a sick animal with it.

This is one of the reasons it is highly prohibited to keep wild gotten animals with captive-bred animals no matter what unless they are properly quarantined.

This is because wild-bred are always far more immune to some diseases than captive-bred, although they might not be affected by such diseases and Parasites. After all, their immune system is strong, but captive-bred will be infected immediately after they come in contact.

We all know that sick animals always lack appetite and it could be because your Blenny fish is sick, so get a vet to do his job.

6. Poor Quality Food: Sometimes the nature of the food you give them could be the reason they are refusing to eat.

We all know that all fish are scavengers and could eat till their stomach explodes if possible, but if yours is refusing to eat, it could be as a result of poor quality or expired food such as pellets and flakes, etc.

I suggest you buy your fish food from reputable dealers and also give them live food such as Copepods, Mysis shrimps, Brine shrimps, insects, larvae, etc.

The idea of giving them live foods is because the movement of the foods will attract them.

What Should I Feed My Blenny?

Blennies are scavengers and would eat anything eatable, so you can literally give them anything other fish could eat.

Blennies could be fed with Crustaceans such as Brine shrimps, Copepods, and Mysis shrimps. Plants and vegetables such as algae, cucumber, watermelon, carrots, etc. Other animals such as Larvae, Snails, Tiny fish, Grasshoppers, Insects, etc. Manufactured foods such as Pellets, flakes, etc.

The fact is, once you see a particular food another fish or aquarium animal eats, give it to your Blenny and it will eat it and still be alright, so they can eat anything you can think of that fish could eat.


These are the most common reasons why your Blenny fish could stop eating and the possible solutions.

I hope this article is helpful to you, good luck.