Reasons why Fishes Refuse to Eat their Feed and How to Correct it

Maybe you have a similar case like this question ”I introduced coppens (imported feed) to my fish after stocking and for the first 4 days, they refused eating it. What could have happened and what do I do? ”

A similar experience had occurred when some tadpoles had grown in the water before the fish were put in the pond. I discovered that the fish were busy feeding on the tadpoles for the first one week before they started picking the floating pellets.

Something related to this may be your own reason also. They can also do that if they were transported from a long distance and do not recover from the stress on time.

To correct this, make sure you give them anti-stress if they are transported from a long distance and also control the growth of tadpoles in your water before stocking so that they don’t refuse the quality feed they need.

Appetite loss are commonly due to diseases that are related to water conditions, infectious diseases, non-infectious diseases, bad food and more. In most cases, when one fish is sick, there is the potential that the entire fish population is at risk of getting sick.

Note that the use of non-targeted medicines for fish diseases without a proper diagnosis could cause more harm and complicate the matter. This could lead to more pain and suffering.

Sometimes, your fishes may also refuse to eat their feed due to the following reasons below:

1) Water

Water quality is the single most important factor for good fish health. They live in it, swim in it, breathe in it and excrete into it. Many biological processes depend on the water conditions to be just right for the type of fish.

As such, fish can lose their appetite if there is a build up of fish wastes (e.g. ammonia, nitrite or nitrate), if the water temperature is too low or too high, if the dissolved oxygen is low, if the dissolved carbon dioxide is high, if the pH is wrong and if there are toxins in the water.

It is thus important to check these parameters when investigating the reason for loss of appetite. There are many different aquarium water test kits available at your local fish shop.

2) Pregnancy

Live-bearing fish may not eat as much as usual right before giving birth. If you suspect your fish is pregnant, move her to a breeding tank where she can have privacy and protection and a secure environment in which to give birth.

Typical signs of live-bearing fish pregnancy include a swollen abdomen and a dark triangular marking toward the lower fin. You may even be able to see the dark spots of the fry eyes through the mother’s body.

Read Also: Negetive Effects of Starving your Fishes

3) Illness

A fish that doesn’t eat may be sick. Watch your fish for other signs of illness, such as staying in one part of the tank, appearing listless or swimming abnormally.

Old or sick fish may begin to list or swim on one side. This could be a natural age-related progression of an older fish or a sign of illness that can be treated. Consult a vet for an evaluation.

4) Stress

Stress can sometimes cause a fish to not eat. Stress can occur when a fish is transferred from one tank to another for cleaning or moving, or if the tank temperature suddenly changes. Saltwater fish are more susceptible to temperature-related stress than freshwater fish.

The addition of other new tank mates can also temporarily stress your fish and shy them away from food. Limit the stress on your fish by conducting regular partial water changes rather than conducting full-scale cleaning. It will reduce stress and help you maintain an overall healthier tank environment.

5) Fear

Fear can prevent a fish from eating. This is often observed in a community tank in which larger, more aggressive fish frighten away smaller, docile tank mates when competing for food.

To help alleviate this problem, choose fish for your community tank that are relatively the same size and temperament, or feed adequately so competition for limited food resources is reduced.

6) Over-Feeding

If you’re feeding your fish too much, it may appear that they aren’t eating. Make sure you’re providing the appropriate amount. Watch your fish when you feed them to assess consumption and behavior. If a vet rules out health issues, try different brands of food on picky eaters to see if appetite improves.

7) Infections

Infectious causes are many and they will affect your fish’s health and appetite. There are broad categories of disease-causing agents just like in any other animal. These include viruses, bacteria, protozoa, worms, crustacea, fungi and more.

Infectious diseases are most commonly spread by the introduction of new fish and plants into your tank or pond. Any sort of stressors can exacerbate the conditions. With the exception of a few diseases (e.g. white spot disease, fish lice), many require microscopic examination to arrive at a diagnosis.

It is highly advisable that you get an experienced aquatic veterinarian to investigate your fish problems because many diseases produce non-specific clinical signs. With the correct diagnosis, you can use the correct treatments.

8) Food

In terms of non-infectious diseases, the list is just as long. Your fish may have an internal disease, like a tumour or a gut blockage. Perhaps your food has gone off (check the use-by date, smell and check that it has been stored correctly).

Perhaps your fish has just become picky and is bored of eating the same food every day. Along with the branded food you feed your fish try feeding them a variety of live foods. If they are still not eating, don’t leave it too long. Call the fish vet.

Read Also: How to Control Feeding Struggle among Fishes in the same Pond

The Dangers of Uneaten Fish Food

Let’s face it, it’s fun to feed our fish! It’s one of the few ways we get to interact with them, and it’s a great way to get shy fish to come out so we can observe them.

Unfortunately, overfeeding is not only detrimental to your fish, but also to the overall health and well-being of your aquarium. Here are some negative effects uneaten food can have on your aquarium:

  • Uneaten fish food releases toxic ammonia and nitrite as it decomposes. This is especially dangerous to newer aquariums where the nitrifying bacteria that gets rid of these toxins hasn’t had a chance to fully develop. High ammonia and/or nitrite levels can stress and even kill your fish. This problem is even more severe in small aquariums where toxins can reach lethal levels quickly.  
  • The decomposition process uses oxygen, which lowers the dissolved oxygen content (DO) in the water and stresses your fish. Since DO decreases at higher temperatures, the effects are more severe in warmer aquariums that are in the upper 70’s to mid-80’s. Poor water circulation compounds the problem.  
  • The breakdown of organic material lowers pH by releasing carbon dioxide, which is converted to carbonic acid in water. In soft water aquariums or those with low buffering capacity, pH can quickly drop below the safe range for many fish species, especially those that prefer more alkaline or basic conditions.  
  • Uneaten food can clog your filter, decreasing its efficiency and reducing circulation in the aquarium. This may result in a low dissolved oxygen content, a drop in pH, a rise in ammonia and nitrite levels, and general stress to your fish. Decomposing fish food also offers a place for mold and fungus to grow.   
  • Excess food causes a rise in nitrate and phosphate levels, which contributes to increased algae growth. Poor water quality also stunts your fishes’ growth, causing their colors to fade and lowers their resistance to disease.  
  • Fish can suffer from obesity and the negative effects on their liver, kidneys and other internal organs.

Read Also: Importance of a Fish Feeding Point in a Fish Pond

Here are some other amazing fish farming books to guide and assist you further below:


Have you visited our Market Place Today? Follow this link to visit Market Place now to check out our affordable products & services that might interest you and solve your current needs at a very cheap price. You can also Advertise your Own Products & Services at the Market Place for Free by clicking on this link to Get Started!

Create a thread for all your related questions to get answers from other members and professionals in the field. Click here on the “Questions & Answers” Section to view or submit your Questions or Answers to previously asked related questions.

Benadine Nonye

An Agric. Consultant & a Blogger - National Diploma in Agricultural Technology - Bachelors Degree in Agricultural Science Education - Masters Degree in Science Education... Join Me On: Twitter: @benadinenonye - Instagram: benadinenonye - LinkedIn: benadinenonye - YouTube: Agric4ProfitsTV - Pinterest: BenadineNonye4u - Facebook: benadinenonye.

Leave a Reply

Your email address will not be published.