9 Reasons Why Your Molly Fish Could Stop Eating And What To Do

Why is my Molly fish not eating?

As a Fishkeeper and fish lover, it could be very painful and disheartening to see your fish stop eating. Fish as voracious eaters, and would eat many things, this is why you know that there is a problem when they stopped eating all of a sudden. In this article, you will learn the possible reasons why your Molly fish could stop eating, and what you should do.

Why is my Molly fish not eating? Molly fish could stop eating if it is constipated, if it is stressed or if it is sick.

These are some of the reasons why they could be snubbing your foods, but many factors could cause that, which we will look into in this article.

Molly fish and many other aquarium fish are omnivores, meaning, they could eat both plants, vegetables, and even animals they could kill, and even decayed animals too and other rubbish.

So, they are considered to be scavengers that could eat anything, so it is very abnormal when they refuse to eat, despite any food given to them.

So, if your fish is refusing to eat foods, then there are many reasons why they could be doing that, and you will learn all about them in a minute.

Why Is My Molly Fish Not Eating?

The possible reasons why your fish is refusing to eat are:

1. Because Of Poor Quality Foods: Being able to eat many things doesn’t mean they like everything and everything they eat is healthy to them.

Some foods could deteriorate their health and might make them sick if eaten in large quantities.

Some foods lack some vital vitamins and some could hurt your fish, especially the expired ones, and could cause constipation, which might make your fish to start rejecting foods.

There are many good-quality foods out there, so the more quality, the better.

Although Mollies could eat a lot of things, their ideal meals are brine shrimps, insects, fish pellets and flakes, worms, etc

2. Constipation: Fish will automatically stop eating when they are constipated.

When a fish is constipated, it will start displaying certain behaviors such as refusing to eat anything, hiding at the bottom of the tank, either in the substrates or in the caves and gravels, etc, the fish will be bloated and will start swimming erratically.

This is caused by some dry foods which will expand in your molly’s stomach, and later on, block the digestive tract.

A molly fish with constipation will either eat little or no food at all.

So, constipation is caused by poor quality foods, overfeeding, or if the fish swallowed a large object, and it is blocking its stomach, esophagus, or even the digestive system,

Constipation is very deadly, as it might starve and even kill your fish if the proper treatment is not given.

3. Stress/Bully: These two factors could affect the overall health and eating habit of a Molly fish.

Mollies in nature do not like getting stressed, and no fish like it either, when they are Stressed or bullied, they may choose to hide in caves or substrates to outrun the bullies and stress too, thereby avoiding foods.

Many factors could cause stress for fish, and some of them are unsuitable tank mates, which could likely result to bully and aggression, wrong water parameters, and some harmful chemicals.

When some of these agents of stress like chemicals are in the water, the animals in such water could hardly be healthy and normal, because their health will deteriorate, and they will suffer from many things, including the inability to eat.

4. Sickness/Diseases: Another great reason why any animal, including fish, could stop eating is that they are sick.

Just like human beings, every other animal do lack the appetite to eat when they are sick, and so does Molly fish too.

When they become sick, they will lack the urge to eat and will start rejecting foods, including their best.

Molly fish are somewhat hardy, but they are prone to many diseases, and so, could easily get sick as a result of contacting them.

Some diseases that affect them are fin rot, white/black spot, etc.

Some of these diseases could come as a result of their living conditions, such as the type of water they’re in, the type of tank, exposing them to unhealthy or diseased animals, etc.

5. Uncycled tanks: There are many disadvantages of keeping your aquarium animals in a tank that was not fully cycled or not cycled at all.

The issue of an uncycled tank is a monster that haunts many fish keepers, and it constitutes a large percentage of the problems which many aquarists have with their animals.

When a tank did not complete its cycle or is not cycled at all, it becomes very toxic and deadly to any animal that might get into it, and it could breed bad chemicals such as ammonia, nitrates, chlorine, copper, nitrites, etc.

The bitter truth is, some of the things attributed to wrong water parameters and unclean water are a result of uncycled tanks.

As we all know, it is only a healthy and comfortable animal that could eat, so this might be the reason your Mollies are unhealthy and unable to eat.

6. Wrong water parameters: As you must have known by now, every aquatic animal has a specific type of water and water quality that are suitable for it, and when such animal is not kept in such type of water, it becomes wrong water parameters and could cause some problems for the animal involved.

Molly fish are tropical and freshwater fish, their ideal water parameters are temperature 72 to 78°F, pH 7.5 to 8.5, and hardness 15 to 30dGH.

They could have problems when kept in a type of water that doesn’t have the qualities described above, and so it could cost them their appetite to eat, and so, that may be why yours is refusing to eat anything.

7. Wrong Water Temperature: As I explained above, every animal has a specific temperature that is suitable for it, and when they are in a temperature that is not what they require, it becomes a problem.

Mollies are tropical fish and do enjoy staying in a moderate or temperate environment which is at 72-78 and slightly 80°F.

When the temperature is much hotter, it evaporates the oxygen in the tank, thereby putting the fish at risk of suffocation and if it is very cold, it will affect their health, making them adjust their metabolism by slowing it down, which in return will stop them from eating.

8. Molly fish are known to reject or avoid foods when they are new in an environment.

There are many reasons why they do this, and one of them is lack of acclimation.

When a fish is new to a tank, it will take some time for it to master the new environment and become used to it, but at first, it will behave very oddly and as time goes by, it will become used to the environment and start being active and will be eating again.

Acclimation is the process of making new aquatic animals master their home or new home.

This is done by keeping the animal in a bag filled with water and placing the bag on top of the water where they will be staying, and be releasing the tank water inside the bag small until the water in the bag is mixed up with that of the tank. Then release the fish to the tank fully.

Many people don’t know this, and it saves a lot of problems.

So if you release a Molly fish or any other fish in a tank with proper acclimation, the fish might stop eating and might fall sick.

9. Your Molly might have stopped eating because she is pregnant.

Normally, when fish becomes pregnant, their attitude will change in many ways, they might reduce their level of activities and also their level of eating.

You will know when the stomach bloat or gets fat.

What To Do If Molly Fish Is Not Eating

You now know the possible reasons why your Molly fish might be refusing to eat anything, now the question is, what will you do to prevent it, and how will you solve the issues? Well, the first step in solving the problem is to identify the cause and then tackle it with the tips I will give below.

1. Make sure they are in healthy water and also they are in their ideal water parameters.

Once you find out that the problem of your fish is poor water quality, try to improve the water quality of your tank by changing the water to more clean and chemical-free water.

Try as much as possible to change the water at least once in 2 weeks, depending on the population of animals in the tank.

2. Always check the water to know if there is any chemical in it. Get yourself water testing kits and do it every week and if there is, change the water at once.

3. Allow your tank to fully cycle. An uncycled tank could be very bad for animals, so cycle yours until it is read.

4. Avoid keeping your fish with aggressive tank mates and keep them at the ratio of 3 females per 1 male to stem aggression and stress too.

5. Once you notice that your fish is constipated or sick, try as much as possible to get a Vet. I won’t advise you to start meddling with a health issue unless you are a vet.

How Long Can Mollies Go Without Food?

An adult Molly fish could go up to 2 weeks without eating anything and will still survive.

Some factors that could determine how long they could go without food are the age of the fish, as Molly fry can’t go for more than 2 days without food, also how well the fish is being fed previously and how healthy the fish is.

You can’t expect a sick Molly fish to go for 2 weeks without food, it will just die, and you can’t expect a fish that is suffering from malnutrition to go that long without food too.

So how long a Molly could stay without food is heavily determined by how healthy it is and how it is previously being fed.

How Often Do Molly Fish Eat?

Fish should be fed once or twice a day with quality food.

Although they are voracious eaters and will continue to eat even if they are okay, in that case, could Overfeed, which could become a problem of its own.

So, the normal feeding method of Mollies and other fish is twice a day.

Are Mollies Always Hungry?

When it comes to food, all fish could eat even without getting hungry, for the fact, they could see food.

Mollies are not always hungry, but they will eat whether they are hungry or they are not, as long as there is food around.

This is why it is very important to regulate the amount of food you give them to twice or once a day for them not to Overfeed themselves or have some leftover foods, which could deteriorate the water quality.


These are the reasons why your Molly fish could refuse to eat, and I hope yours start eating. Good luck.