Why Is My Pregnant Guppy Not Eating? (And How To Fix It)

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I was a bit stressed when I first grew a pregnant guppy fish. I was even more worried when I found out the fish had not eaten all day. Luckily, as time passed, I gained some experience in this field. Apparently, a loss in appetite can be a natural response to pregnancy.

Pregnant guppies typically stop eating due to the pregnancy, especially when they approach their due date. At this stage, your guppy will also hide and breathe heavily. However, some guppies won’t eat because they are kept in a breeding box for too long or suffer from the wrong water parameters.

As we move forward, I will list all the causes behind a pregnant guppy fish that has lost its appetite. Then, I will mention some practical steps to fix this issue.

Still curious? Feel free to check my complete guide on pregnant guppy fish. There, I discussed how to care for pregnant guppies, how long they remain pregnant, how to identify signs of pregnancy, and a lot more.

Why Is My Pregnant Guppy Not Eating?

You have to give guppies nutritious meals every day. This is especially true for pregnant guppies because they are so vulnerable during their gestation period.

But what if your pregnant guppy refuses to eat? You cannot help the fish until you identify the factors that have extinguished its appetite. They include:

1. It’s Due To The Pregnancy 

Pregnant guppies will eventually lose their appetite. Some females will continue to eat, but the quantities they consume will decrease drastically. Others will stop eating altogether. This will occur gradually.

A loss of appetite is entirely normal in such situations, and it shouldn’t cause panic. You must continue to feed the guppies. However, reduce the quantities. Give them smaller meals.[1] But make sure you remove the leftovers.

2. There Is A Problem With The Food

Before you blame the fish, take a look at the food. You have several significant considerations to make, including:

  • Expiration Date

Have you looked at the expiration date on the packaging? In most cases, fish will eat whatever you give them, even when it isn’t good for them. 

However, pregnant fish have little or no appetite, so they are less likely to tolerate expired food. They will nibble on the food before ignoring it.

  • Size

Fish are not like humans. They can’t tear large pieces of food into smaller chunks. If a particular food item is too large to fit in a pregnant guppy’s mouth, the fish will move on. 

Healthy guppies can break sizeable items into manageable pieces, but pregnant females are less patient. 

  • Rigidity

If the food is too hard, the guppies will eat it and spit it out. This is why some aquarists soak flakes before adding them to the tank. They want to make the food as easy for the guppies to chew as possible. 

  • Preference

Guppies are omnivores. They will eat animal and plant-based foods like algae and mosquito larvae.[2] For the most part, they are not particularly difficult to feed.

They eat most of the same foods that other omnivorous fish enjoy, including frozen, live, and freeze-dried items. However, like humans, guppies have unique personalities. Some of them are picky eaters.

This may not become clear to you until you place the pregnant female in a separate tank and it starts rejecting every food item you have on hand. You have to experiment with different options until you find something the expectant mother likes.

3. Your Guppy Is In A Breeding Box

Is your fish in a breeding box? Breeding boxes are convenient because you can protect pregnant guppies from enthusiastic males without taking them out of the tank.

But breeding boxes are dangerous because they induce significant amounts of stress. This is why aquarists wait until a guppy is close to giving birth before placing it in the box. 

Where possible, the guppy should leave the breeding box within 24 to 48 hours. A guppy that lingers in the breeding box is more likely to stop eating. This doesn’t happen with every guppy. Some fish are more resilient than others. 

4. The Guppy Was Moved To Another Tank

Separate tanks are not as dangerous as breeding boxes. However, they can also induce stress because you have taken the guppy out of its home. Healthy fish struggle with shock and anxiety whenever you add them to a new tank.[3]

Pregnant guppies are not healthy. They have heaps of stress to overcome because of the dozens of babies in their bellies. Moving the creatures to a new tank will exacerbate that stress, banishing their appetite in the process. 

5. Your Guppy Has Just Given Birth

Has your guppy just given birth? If so, it needs to recover. If you keep it in a separate tank for a day or two, it may not eat during this period.

If you take the guppy back to the main tank the moment it pushes out the last fry, you will disrupt its recovery because it has to contend with the attention of males that want to mate.

The males may hound the female to death. If it survives, the mother may refuse to eat for several days, possibly even longer.

6. The Water Quality Is Inappropriate 

Fish are sensitive to poor conditions in the water. They also hate fluctuations. A combination of poor conditions and fluctuating parameters will either kill the guppies or ruin their appetite.[4] 

You have to test the water regularly to protect the fish. Water changes are vital, but you have to keep them small. A significant water change will achieve the wrong result. It will cause such drastic shifts in the parameters that the guppies may respond by aborting their offspring.

These are the ideal water parameters for pregnant guppies: 

  • Temperature: 75–80° F (24-27° C) 
  • Water pH: 6.9–7.5 
  • Hardness: 9-10 dGH 
  • Ammonia and nitrites: 0 ppm 
  • Nitrates: <20 ppm

To measure the ammonia, pH, nitrates, and nitrites, I personally use the API Water Test Kit (link to Amazon). This one costs a bit more than average. However, it is incredibly accurate. It also lasts for eight hundred measures, making it highly cost-effective.

If you’ve detected significant spikes in ammonia, use water conditioners. I personally recommend the well-known Seachem Prime (link to Amazon). Using a few drops of this product will induce less stress than a water change.

You can perform significant water changes once the guppy gives birth. Also, you don’t have to perform massive water changes to keep the tank clean. You can remove dead and decaying matter, vacuum the substrate, maintain the filters, and more. 

7. The Temperature Is Out Of Range

Avoid extreme temperatures. Cold water will lower a guppy’s metabolism.[5] It will become slower and sluggish. Naturally, in this state, the fish’s appetite will disappear. This is true for pregnant as well as non-pregnant guppies. They can easily starve.

But if the water is hot, the fish will become hyperactive, which seems like an improvement if your guppies were lethargic. But that hyperactivity will give way to stress, and the pregnant females will stop eating once again.

If that isn’t bad enough, the high temperatures will create an oxygen deficiency. Don’t expect fish in oxygen-deficient tanks to eat. So, as was I previously noted, aim for 75–80° F (24-27° C).

8. Your Guppy Is Carrying A Disease

Sick fish are just like sick humans. They have no interest in food. Unfortunately, pregnant guppies have weak immunities. In other words, they are more vulnerable to diseases like ich and fin rot than their non-pregnant counterparts.

Diseased guppies are sluggish and have abnormal swimming patterns. Unfortunately, that is true for pregnant guppies as well. 

Unless your fish have developed unusual symptoms such as white spots and skin lesions, you may not realize that the creatures are sick until it’s too late. After all, loss of appetite is common in pregnant guppies. It is not unique to sick fish.

If you noticed any of the symptoms above, you should consult a vet. They will do a better job of identifying and interpreting the guppy’s symptoms.

What Should I Do If My Pregnant Guppy Refuses To Eat?

As you can see, numerous factors may force your guppy to lose its appetite. Start by ruling out causes that can potentially harm your guppy, such as inappropriate water conditions. You can use the testing kit linked above.

Then, check if the temperature falls between 75 and 80° F (24-27° C). If the water is too hot or too cold, you may lower or raise the temperature, respectively. Make sure you do that gradually. I would suggest changing a single degree each day or two.

In case your guppy is in a breeding box, make sure that it isn’t too early for that. Here is an article where I discussed the guppy fish pregnancy stages. Guppies are typically pregnant for 21 to 31 days. So, it is best to use a breeding box between days 25 and 31.

If your guppy is kept in a separate tank, you should consider moving it back to the original. Generally, I suggest moving the tankmates themselves instead of the pregnant guppy. This way, you can avoid unnecessary stress.

If you found this article helpful, these may also interest you:

Pro tip: If your guppy is pregnant and will give birth soon, you’ll need to know a little more about the babies. On that matter, feel free to check my complete guide on guppy fry.


Pregnant guppies typically stop eating when they are stressed. Surprisingly, the pregnancy itself can be the leading cause of stress, especially when the fish is about to give birth. In this case, the fish will regain its appetite after all the fry are born.

However, you must rule out environmental factors, such as temperature, ammonia, pH, and toxins. If you find some abnormalities, make sure that you fix them gradually. Abrupt changes will induce more stress.


  1. https://fishtankadvisor.com/pregnant-guppy/
  2. https://animals.mom.com/feeding-habits-guppies-4777.html
  3. https://fishcareguide.com/why-is-my-fish-not-eating/
  4. https://www.fishtankreport.com/fish-not-eating/
  5. https://fishkeepingforever.com/why-are-your-fish-not-eating-9-possible-reasons/