Why Is Goldfish Spitting Out Food?

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It’s undeniable that goldfish are excellent tank fish, displaying a friendly demeanor, an amazing diversity of colors and patterns, and impressive resilience to adversity.

That being said, it’s also not a secret that caring for them isn’t exactly a walk in the park.

Your goldfish require specific conditions to thrive, which include:

  • Stable and optimal water parameters, since fluctuations in temperature, pH, hardness, or in the water’s chemical composition can hurt them
  • A stress-free environment, given that goldfish, are shy and friendly fish and don’t cope well with aggressive tank mates
  • A well-crafted tank set up with plants and various aquatic decorations for some environmental diversity
  • A diverse and balanced diet for optimal nutrient intake

Today, we will discuss the latter, aiming to shed light on goldfish’s diet and feeding habits.

One of the common feeding problems that most novice aquarists face is the goldfish spitting its food. Why do goldfish do that, and how can you prevent it? Let’s have a look!

Reasons Goldfish Spit Out Food

There are 7 reasons why your goldfish may reject the food, each indicating different problems that require immediate tackling.

These include:

1. Wrong or Bad Food

While goldfish are omnivorous, marketed as eating ‘anything you throw at them,’ that’s not entirely true. It’s true that goldfish are omnivorous, but they won’t eat quite anything.

There are around 200 species of goldfish available, many of them being the result of selective breeding. While they all share similar features and food preferences, they are not identical.

What may appease some won’t appease others, which means it also matters what your goldfish likes to eat, not only what it needs to it.

When it comes to commercial food, different products come with different ingredients and tastes. Your goldfish may exhibit preferential behavior, preferring some foods over others.

See what it likes and prioritize those foods, so long as they also pack the necessary nutrient content.

Aside from that, your goldfish is also capable of detecting bad or expired food. In most cases, at least.

So, if your fish refuses food that it once liked, check the expiry date. Feeding your goldfish expired or spoiled food will cause digestive problems if the fish eats it or starvation if it refuses it.

Not to mention, feeding your fish inadequate food will result in more leftovers since your goldfish won’t eat as much or at all.

These residues will sink to the substrate and decay, altering the water’s chemistry fast. The result is more ammonia and nitrites, which can cost your goldfish their lives.

So, if your goldfish spits out its food, check the food’s specifics, expiry date, and quality before looking into anything else.

2. Impaction

In laymen’s terms, impaction primarily stands for constipation, but it generally describes the act of displaying a clogged intestine.

In fish, the notion of impaction mostly refers to constipation and is mostly the result of overfeeding or digestive problems due to various disorders and or genetic faults. Overfeeding, especially, is a widespread problem among goldfish since these are notoriously voracious eaters.

In short, goldfish will eat as much food as is available, which can often cause digestive problems. Impaction is one of them. When that happens, the goldfish will display an inflated abdomen, show an inability to poop, and refuse food.

If overfeeding is the cause of impaction, the solution is simple. Put your goldfish through a period of 2-3 days of fasting, as this will allow its digestive system to eliminate the surplus.

Then, learn how to feed your goldfish correctly. Adult goldfish shouldn’t eat more than 2 times per day and only enough food for them to consume within a couple of minutes. Anything more than that is excess.

Plus, aside from causing digestive problems, overfeeding can also result in more fish waste and food residues. These are the perfect ingredients for ammonia spikes in your goldfish tank, and you don’t want that.

3. Mouth Problem

Goldfish can experience several mouth problems, including bacterial infections like cotton mouth, mouth fungus, and even diseases like enteric red mouth disease. These conditions are responsible for a lot of discomforts and will come with more generalized symptoms, depending on the disorder’s profile.

The fish will display a variety of symptoms, some physical and some behavioral, and one of them is the refusal to eat.

Your goldfish may either spit out the food or avoid it altogether. At this point, you should look for additional signs of disease that may paint a clearer picture.

Some worrying signs include:

  • Unexplained changes in coloring
  • Swollen abdomen
  • Protruding eyes
  • Enlarged lips with white growths around the mouth
  • Torn tissue around the mouth and lips, etc.

The symptoms may differ slightly, depending on the condition and its development, but one thing is certain: immediate treatment is vital.

If you detect the presence of additional symptoms, I suggest quarantining the fish immediately. Many of these conditions are contagious and will quickly infect the rest of the goldfish population.

After you’ve quarantined the sick fish, ensure impeccable water conditions and consider using an antibiotic.

If you’re unsure what medication to use for your particular case, discuss with a goldfish specialist before getting any over-the-counter drugs.

4. Water Quality

If the water conditions are poor or unstable, your goldfish may exhibit stress, during which it may refuse food. This generally happens as a result of temperature shifts during water changes.

Even a sudden variation of 4-5 degrees can disrupt your goldfish’s comfort level, causing it to display signs of stress like hiding behavior, altered appetite, aggression, etc.

You can prevent that by monitoring the water temperature during the procedure to make sure there are no significant variations in its values.

Another pressing problem is that of ammonia buildup. Skipping your tank maintenance routine can lead to algae overgrowth, ammonia buildup, and an overall dirtier tank with murky waters.

Your goldfish won’t feel comfortable in such an environment and may even display worrying signs like ammonia stress, suffocation due to low water oxygen, or a complete lack of appetite.

To prevent that:

  • Invest in a filter – A well-rounded filtration system is a must in any goldfish tank. Make sure you find a suitable system providing chemical, mechanical, and biological filtration to ensure a clean and healthy environment. The filter will remove large and fine floating particles, eliminate a variety of microscopic pathogens, and even dilute dangerous chemicals like ammonia and chlorine. The result is a cleaner and healthier environment for your goldfish to enjoy.
  • Regular tank maintenance – Remove algae overgrowth and vacuum the substrate regularly to cover for the filter’s blind spots. While the filtering system is a necessary addition to your goldfish tank, don’t rely on the equipment to do all the work. You also need to do some cleaning yourself to remove dead organic matter and residues buried in the substrate that could affect the water’s quality.
  • Regular water changes – Your goldfish typically require one water change per week. You shouldn’t change more than 10-15% of the water to avoid disturbing the tank’s biofilm in the process. The frequency of the water changes varies depending on the tank’s size and how many fish you have. This phase is essential since it dilutes ammonia and nitrites, preserving the system’s stability and protecting your fish.

As a plus, you should clean the filtering system at least once every 4-6 weeks, depending on how dirty it gets.

Otherwise, it risks getting clogged or overburdened with algae overgrowth, diminishing its efficiency considerably.

5. Stress from Mates

Goldfish are social creatures and feel more comfortable in larger and stable societies. The problem is that, however peaceful they are, goldfish will sometimes display aggression towards each other.

Male goldfish will compete over hierarchical ranking, food, females, and space, often leading to confrontations and even more serious battles.

In these situations, the more imposing fish will always bully the weaker ones into submission. The bullied will be forced into hiding and will soon display signs of stress like refusing food and appearing lethargic.

The same problems occur when pairing goldfish with more aggressive fish species attacking or bullying them.

Your goldfish won’t fight back since they are rather shy fish. They will initially look to hide from their aggressors, but they will soon become stressed if the situation doesn’t improve.

To avoid these situations, consider:

  • Upgrading the tank – If you feel like the goldfish are too aggressive, consider changing your current tank for a larger one. Your goldfish could always use the extra space as it lowers their aggression and improves their comfort. They will also have more room to flee from their aggressors.
  • Adding more plants and aquatic decorations – Plants and decorations are necessary for any goldfish tank. Aside from adding some esthetic diversity, these elements also create more hiding spots and break the line of sight between the tank occupants. This makes them useful additions if you need to calm your fish and lower the level of tank violence.
  • Removing the culprit – Sometimes, when all other options fail, you’re left with the obvious, and that’s removing the aggressors from the tank. This will create more room for the remaining fish and contribute to a calmer and more stable environment.

6. Gills Problem

Gill problems differ in nature, depending on what’s causing them. Your goldfish may experience a variety of gill-related issues, including injuries, fungal infections, and even conditions like bacterial gill disease.

These problems will cause localized discomfort, preventing your goldfish from enjoying its meals and even disturbing its appetite.

If your fish spits out its food, look for any visible signs of disease or injury around its mouth and gills.

If you notice mucus hanging out of its gills, localized redness, open wounds, bleeding, swelling, or signs of infection, consider quarantining the fish immediately. You may have a bacterial problem at hand.

Such a condition is dangerous since the gills are vital organs that control the fish’s breathing. Immediate treatment is necessary, which may include using antibiotics and other medication designed to control and eliminate the condition’s causes. Make sure you place the goldfish in a stable and clean environment for the entire duration of the treatment to improve its recovery chances.

7. Sickness

Reduced appetite and refusal to eat are common symptoms present in a variety of disorders. The problem is that you can’t use your goldfish’s lack of appetite to diagnose its health problem.

Instead, you should look for as many symptoms as you can find to make sure you diagnose its condition accurately.

And I can’t stress this enough but quarantining your goldfish is essential in these cases. Especially since you have no idea what you’re dealing with.

Goldfish may experience loss of appetite for many reasons, including chlorine, nitrite, ammonia poisoning, Ich, swim bladder disease, fungal and bacterial infections, parasites, etc. They will also refuse to eat due to high levels of stress or fish aggression, forcing them into hiding.

Whatever the cause may be, quarantining the fish allows you to assess the situation calmly without risking the health of the other tank occupants. After you’ve diagnosed the condition accurately, begin the treatment and hope for the best.

Goldfish are resilient creatures and will recover provided the condition isn’t too severe, and you detect it in its early phases.

Do Goldfish Chew Their Food?

Yes, they do. This may come as a surprise, but goldfish have teeth. The problem is that these are pharyngeal teeth located at the back of the throat, so they’re not visible.

The goldfish uses these teeth to grind the food before reaching their intestines.

An interesting fact here – goldfish don’t have stomachs. This explains their predisposition to digestive problems associated with overfeeding.

The food simply doesn’t have time to digest since goldfish who eat more than they’re supposed to don’t take time to chew properly. The food will just accumulate in their intestines and lead to compaction, which can be fatal.

So, yes, goldfish chew their food to aid in digestion. You can even hear them doing it if you listen closely.

The sound is somewhat of a faint wet click caused by the fish’s lips and its teeth grinding the food. Cute and fascinating at the same time.


Goldfish are rather picky eaters, and while they consume pretty much the same foods, their preferences change among the different species.

For a comprehensive TL:DR section, here are the main points to consider if your goldfish refuses food:

  • Make sure your goldfish loves the food and that the product isn’t bad or expired
  • Check your goldfish for signs of disease, bacteria, or parasites
  • Check the goldfish’s mouth and gills for injuries or bacterial growths
  • Monitor water quality to ensure optimal and stable parameters
  • Prevent fish aggression

Once you’ve identified the cause, adopt the adequate fixes, and your goldfish should rebound immediately.

These are hardy fish that won’t go down without a fight. They just require your support and care along the way.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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