Everything You Ever Wanted To Know About Feeding Goldfish

Goldfish are one of the most commonly stocked fish breeds in the world.
Goldfish are the descendants of Chinese carp, and they were first “domesticated” in China over 1,000 years ago. Today, you can find goldfish in homes, classrooms and offices all around the globe.

So, if goldfish have been around for this long, you might think that they must be pretty easy to look after, right?
Wrong! Many people think that goldfish are hardy, tough fish who can handle neglect – whether that means a dirty tank or irregular feeding.
However, nothing could be further from the truth. Goldfish don’t thrive on neglect or inconsistent care – and neither does any other kind of fish.
In fact, goldfish have very particular needs when they’re in a captive environment, whether that’s a tank or a pond. To do well in a domestic aquarium, they need cold water, a sparkling tank, and plenty of other essentials.

Of course food plays a major role.
Feeding your goldfish the right kind of food, in the right amounts, is an essential part of your care routine. If you make mistakes here, it can have devastating consequences for your pets.

In this article we’ll cover everything you need to know about feeding your goldfish.
From the type of food they most enjoy, through to feeding times and routines, dietary supplements and food sources, you’ll have everything you need to keep your goldfish happy and healthy.

Did you know that goldfish don’t have a stomach – and that they’ve actually got teeth?
It’s true! Your seemingly “ordinary” little goldfish is actually quite an extraordinary animal.
In this section we’ll cover some of the anatomical curiosities that make goldfish special and that you need to know to understand how to feed them.

Goldfish have teeth

Goldfish have a few small teeth in their jaw that they use to bite and tear their food. Surprised?
They also have a set of teeth hidden away at the back of their throat.
The teeth in their throat are called “pharyngeal teeth” (as they are located in the pharynx, which is just behind the nasal cavity and mouth, and right above the oesophagus). They’re not “biting” teeth – instead, goldfish use them to help crush their food.

Goldfish have a special kind of jaw to help them feed

Goldfish also have something called a “protractile jaw”, which is a jawbone that can be pushed forward while they’re feeding. You’ll see them using this when they’re foraging through the gravel or substrate at the bottom of your tank looking for food.
Goldfish use their jaw to help bring the gravel and/or food into their mouth, and then spit the gravel out again after they’ve sieved out the food.

Goldfish don’t have tongues

Your goldfish doesn’t have a tongue, just a gullet. So how do they taste their food?
Goldfish have taste buds distributed all over the inside of their mouths, as well as
around their lips on the outside.
In addition, over 20% of a goldfish’s brain is dedicated to their sense of taste.
This capability is one of their most important senses.
Goldfish use their whole mouth to find their food, and then taste it. You see this in action when they are sifting through the gravel at the bottom of their tank – they will take some gravel into their mouth along with a tidbit of food, and then spit the gravel out.

Goldfish don’t have stomachs

Perhaps the most unexpected of all their anatomical features is the fact that goldfish don’t have any kind of stomach. So how do they digest their food?
It means that food is broken down and absorbed through different parts of the intestinal tract, which is surprisingly long – about twice the length of their body.
This curious anatomical fact is one of the reasons that goldfish process their food so quickly – and also the reason they produce a lot of waste.

Without a stomach, there’s nowhere for food to be stored, and not much can be ingested or digested at once. The food has to keep moving through the goldfish intestines, which means that these fish need to eat a lot… and they poop a lot, too.

Their fast digestive process means that toxins and waste products will build up in a goldfish tank very quickly. This is one of the primary reasons that you need to keep your goldfish tank sparkling clean.
The use of filters in the tank is highly recommended.

The fact that your goldfish doesn’t have a stomach also has an important bearing on what you feed your fish, and how often you feed them. Fancy Goldfish can be especially difficult to care for when it comes to feeding, as the shape of their body and the position of their internal organs can cause more trouble for digestion than garden-variety standard goldfish.
Because a goldfish’s digestive system moves quickly, they need to absorb their nutrients fast.

Soft food works better than hard food that takes some time to be processed internally, as soft food can be broken down into chunks that can be quickly swallowed and digested.

You’ll also need to make sure you feed your goldfish more than once a day, or they’ll go hungry. A few smaller meals each day is probably a better idea.
But goldfish are also notorious over-eaters, and you don’t want to feed them too much or they can bloat and get sick, or even die.

It’s trickier than you might have thought, right? There’s a lot to be mindful of when you have goldfish in your tank.

What do goldfish eat in the wild?

Goldfish are true omnivores, meaning that they can eat both protein and vegetable matter.
In the wild, goldfish will eat from a range of food sources, depending on what’s available.
This includes insects and their larvae, plants, worms, shrimp and other crustaceans and sometimes even other small fish.
They’re greedy, so they’ll eat anything they can swallow.
Goldfish are also foragers, rather than hunters. They’re better at rooting around at the bottom of the ponds, lakes or rivers they live in, sifting the gravel or silt for tasty bits and pieces. They have very sensitive mouths that help them find food, in addition to nibbling on plants for both the nutrition and fiber that they need to help keep them healthy.

Like all animals, goldfish will do well on a diet that closely mimics what they would eat in their natural environment.

If you’re keeping goldfish, it can be a good idea to try to recreate this kind of environment for your pets.

The great debate – commercial food or fresh food?

Here’s a question that creates some robust discussion amongst goldfish owners.
Should you feed your goldfish commercial food, like flakes or pellets, or give them a varied diet of fresh ingredients instead?
Goldfish flakes have to be one of the most commonly recognized fish food products on the market. If you had a goldfish when you were little, you probably fed it with goldfish flakes – unless your parents were experienced aquarists!
Quick and easy, this method of feeding is almost synonymous with goldfish ownership. It ranks up there along with the idea that goldfish can live happily in a round bowl (pro tip: they can’t. Check our previous article for more details).
However, many enthusiasts agree that as a successful goldfish aquarist, flakes or pellets are can be a good food source for goldfish, but they shouldn’t be the only food source.
If you decide to feed primarily flakes or pellets, you’ll need to supplement your goldfish’s diet with additional fiber and nutrients.

Flakes and pellets often have additives and filler

Commercial fish food products can be a little like junk food for your pets.
They’re quick and convenient – like a burger and fries – but just like fast food, they’re not the most nutritious options you can offer your fish.
Although the labels will often say that flakes or pellets are a “complete goldfish food”, this isn’t usually the whole story. The food may be specially formulated to meet all the nutritional needs of your goldfish, but they are less likely to meet all their dietary needs. These are two different things.
The biggest factor here is the carbohydrate content of dry food. Commercial goldfish flakes and pellets are often “padded out” with bulking agents and carbohydrates, and have extra processing and additives.
A goldfish who lives solely on commercial food may have trouble with their digestion or become constipated, just like you would if you didn’t eat any fiber in your diet.
Additional fiber in the form of vegetable material or fruit will help keep them healthy.

Flakes and pellets can cause issues for your fish or its tank

There are other issues to be aware of in relation to dry food feeding and some of the issues it can cause for goldfish.
In their natural habitat, goldfish pick up their food from the bottom or the middle levels of their habitat, not so much at the surface. They also spend a lot of time sifting the substrate to pick up scraps of food.
When they’re fed flakes, which float at the water surface, some goldfish can tend to gulp air at the same time – and this is thought to cause swim bladder issues.
Some other issues to be aware of include:

  • Fish flakes will start to break apart and decompose as soon as they touch the water, clouding the water and adding to the pollution levels in your tank.
  • Flakes will start to lose their nutritional value once their packet is opened and they are exposed to the air – they’ll also absorb moisture and become damp.
  • Pellets can sink to the bottom, where they will start to rot.
  • Pellets will absorb water and can expand to two or three times their original size in your fish’s stomach. This can cause bloating and constipation for your poor fish. If you absolutely must use pellet food, it’s a good rule of thumb to always soak the pellet in some tank water beforehand.

For all these reasons, a diet of dry food alone isn’t recommended. However, you might use flakes or pellets as a basis for their diet and then add additional vegetable material or live food options as treats.

Flakes and pellets can also be useful to have in the cupboard for emergencies, or if you’re going away overnight or through a weekend. Check our article here for lots more information about feeding your fish while you’re away on vacation.

Pellets have the advantage that they’re easier to measure out accurately for beginners or stand-in feeders while you’re away, and they have a longer shelf life once they’re opened, too.

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Some dry food options to consider for your goldfish

If you do choose to purchase some dry food for your goldfish, here are three popular products that you might consider:

  • TetraFin Balanced Diet Goldfish Flake Food

    These flakes are designed to provide a nutritionally balanced diet especially for goldfish, including vitamins, minerals and trace elements. They contain high-protein fish meal as a core ingredient. The makers state that the product stays firm and won’t cloud your tank water.

  • Aqueon Goldfish Granules

    Made only with natural ingredients and colours, these small goldfish granules will provide your goldfish with a diet that meets their nutritional needs. Suitable for common goldfish, fancy orandas or koi. It’s specially formulated so that the fish utilize more of what they eat, creating less waste.

  • Hikari Lionhead Sinking Pellets

    These pellets are specially designed to sink in your tank, meaning your fish can scavenge for them naturally and avoid any potential for air-gulping. Good for premium grade or fancy goldfish, including Lionhead, Orinda, Ranchu and Azumanishiki.

Gel food

Gel food is an alternative food preparation that you can use to supplement your goldfish’s diet, or use as a more primary source of food.
Gel food usually doesn’t contain any bulking agents or artificial additives, so it can be a good alternative to flakes or pellets. You can even make your own gel food at home – check this article for some recipes or pick up one of the many books on the topic.
Gel food is simple to prepare using a setting agent like gelatin or agar agar, and you can include the protein-based ingredients that your goldfish loves. You can also add extra items such as red bell pepper to help improve your goldfish’s color, as well as spirulina, or other vegetables for additional fiber.
You can also buy premade gel food from your pet store or online. Here is an option you might consider:

  • Repashy Soilent Green

    This is a meal replacement gel that can be used for small fish, amphibians, reptiles and invertebrates. You mix it with water and heat in the microwave, and then let it cool at room temperature. Once cooled, you cut it into cubes or shred it into tiny pieces. It will keep in the fridge for 2 weeks, or the freezer for 6 months.

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How you can provide a balanced diet of fresh food for your goldfish

Because goldfish are omnivores, they will benefit from a varied diet of fresh food that can help provide their nutritional requirements as well as their digestive requirements. This means they need to eat both protein and vegetable matter.

Goldfish rely on protein, vitamins and minerals to help build muscle, provide essential nutrients, and support their immune system.
They rely on natural fiber to help keep things moving along their digestive tract.

There is a long list of “human” food that you can offer your goldfish. While they make great food for your fish, they should be supplementary items, not the primary food source.
Some of the items that are high in fiber include:

Vegetables

      • Rice
      • Corn (Always remove the skin of the kernel, just like with a pea)
      • Cucumber
      • Zucchini
      • Lettuce
      • Spinach
      • Seaweed
      • Peas (Never give a frozen pea! Always boil it and peel the skin off. Then mush it up or cut it into quarters so that your goldfish can grab it easily. Here is a quick video on how to feed goldfish peas.

        In general, you should blanch or lightly boil these items before you feed them to your goldfish, as boiling helps to break down some of the cellulosic fibers that can be hard to digest.
        Boiling or blanching also makes the food softer, meaning that your goldfish can get it into their mouths more easily.
        Remember to feed very tiny chunks of these foods – one or two millimetres in diameter is plenty big enough – something about as big as your goldfish’s eye. Your goldfish has no stomach, so it has to grind these tiny pieces using its pharyngeal teeth.
        With spinach and lettuce, you can tear a leaf into smaller pieces instead, or clip a leaf to the side of the tank to make it easier for your goldfish to grab. If your fish tend to suffer with swim bladder problems or constipation/digestive issues, additional fiber in the form of spinach or lettuce can be very helpful.
        You can also plant your tank with live plants that your goldfish will find attractive to nibble on. They love to eat plants – especially duckweed – so it’s a good idea to have a few different types in your tank, so that there’s variation and no single plant suffers too much!
        You can also add some different plants for short periods from time to time as a special treat, such as anacharis.

        Fruit

        You can feed your goldfish tiny amounts of fruit including:

        • Peeled Grapes
        • Peeled Apple
        • Strawberries
        • Oranges
        • Mango
        • Banana

          Think of fruit as a treat though, rather than a regular or daily food item. It’s high in fructose, a kind of sugar, which your goldfish aren’t used to digesting.

          What live food can you feed your goldfish?

          Goldfish will benefit from live food that is similar to what they would eat in their natural environment. These foods include:

          • Daphnia – also known as water fleas
          • Live worms – tubifex worms, earthworms or bloodworms are good options
          • Brine shrimp
          • Aquarium snails
          • Krill
          • Plankton

          Do be aware that if you decide to feed live food to your goldfish, there is a very small possibility that your goldfish can catch disease or parasites from these items.
          A good way to avoid this possibility is to feed your fish frozen or freeze-dried versions. They won’t be as close to the “real life” situation you’re aiming to replicate, but they significantly reduce the small risk of disease transmission.
          Frozen food often comes in small blister packs. You just pop out the food and thaw it, and feed it directly to your goldfish.
          Freeze-dried foods have a long shelf-life and they can be quicker to rehydrate and feed to your goldfish. Here are some freeze-dried options you might like to consider:

          • Hikari Freeze-dried Bloodworms

            A pharmaceutical-grade freeze-drying technique ensures these bloodworms are as close to fresh as possible. These bloodworms are free of parasites and any harmful bacteria, so they are a good option for a goldfish treat.They won’t cloud your tank water.

          • Hikari Freeze-dried Tubifex Worms

            The same pharmaceutical-grade freeze-drying technique is used for all Hikari products. You can feed these to your goldfish as they are, or soak them in a cup of aquarium water first to soften them up and expand them before your fish consumes them.

          • San Francisco Bay Freeze-Dried Brine Shrimp

            These solid cubes of shrimp can be crumbled to a powder or broken into smaller chunks before you add them to your aquarium. Specially raised in enriched saltwater ponds, the shrimp are chock full of essential fatty acids, protein, and pigments that can help keep your goldfish scales shiny and rich in colour.

          Are there any foods that you shouldn’t give to goldfish?

          These are a range of questions you might find yourself asking if the pantry is bare and your goldfish are hungry. Can goldfish eat bread? What happens if you feed meat to a goldfish?
          Improvisation can help in this situation, but be aware that there are some foods you should never give to your goldfish.

          • Try to avoid vegetables that have bitter flavours – things like cabbage, brussel sprouts and broccoli.
          • Don’t ever give your goldfish onions, leek or shallots
          • Don’t feed bread to your goldfish. The carbohydrates are hard for your goldfish to digest and bread will swell in their little intestinal tract
          • Don’t feed anything that isn’t part of their natural diet. No cookie crumbs, nothing with added sugar, no sweets, no salt, no dairy. Use your common sense! Goldfish need protein and vegetable matter, nothing else
          • It’s not a good idea to feed meat to your goldfish. This isn’t something they’d eat in their natural environment, they won’t get the right amino acid balance from it that they need, and they aren’t equipped to digest fats from meat or offal.

          How often should goldfish be fed?

          Goldfish can be little gluttons, and they’re known to beg their owners for food – waggling their little fins and bobbing at the surface. They’re so food-responsive that you can even train them to come to the surface and take food from your fingertips!
          Have a look at this video on how to hand feeding goldfish.

          There’s a good reason for this.

          Goldfish get hungry fast because they have no stomach – but you must be very careful not to overfeed your fish, as it can lead to serious problems such as bloat, indigestion, or death from over-eating.
          A good rule of thumb is that you should feed your fish at least twice daily, and sometimes more – but not for very long each time.

          So, if you feed them three or four times a day, make sure it’s only for 1-2 minutes each time.
          Another way to think about the right amounts is to only feed as much as the size of your goldfish’s eye.
          After the time is up, scoop out any leftover food so that it doesn’t begin to decompose inside your aquarium. This will also help prevent your greedy goldfish from gobbling too much.
          Your goldfish might still act hungry and beg you for food after feeding time is over. Don’t give in! Goldfish are the Labrador dogs of the aquatic world – they will happily eat themselves to death if given the chance.

          How long can goldfish live without food?

          Goldfish can generally go without food for up to around eight days, but sometimes they can last as long as two weeks.
          Two goldfish did once survive 134 days without food after an earthquake in New Zealand – but please don’t try to beat this record…
          In general, leaving a goldfish without food for eight days isn’t a very responsible way of taking care of your fish. If your fish hasn’t got a regular supply of food, it will need to metabolize nutrition from its muscle stores, and this will have a wasting effect on your pet.
          The other factor to consider is that even if your fish survive for eight days without food, they still need their water to be kept clean. Spiking ammonia levels in your tank will kill your goldfish faster than going without food.
          It’s also not a very nice thing to do. Would you like to go without food for eight days? No! And neither does your goldfish.

          How you can feed your goldfish while you are on vacation

          There are plenty of options you can explore in order to ensure your goldfish are looked after and fed regularly while you’re on vacation.
          These include:

          • Automatic fish feeders

            that you fill with fish flakes or pellet foods, and program to drop the food into the tank at the right time(s) of day

          • Housesitters

            Getting a housesitter in to look after your aquarium so that someone is paying close attention and can also keep the tank as clean as it needs to be.

          Check out our previous article for all the details and products that can help you care for your goldfish while you’re away from home.

          Conclusion

          As you can see, there are a lot of factors to consider when it comes to feeding your goldfish.
          Your goldfish needs a balanced diet with a lot of variety, in order to get both the nutritional requirements it needs to thrive, as well as the dietary requirements.
          While commercial foods can provide a good basis, you will do well to supplement your goldfish’s diet with other foods such as frozen or freeze-dried food, live food, and ample vegetable material a few times a week in order to keep them happy and healthy.
          What’s your experience been? Have you found the perfect recipe for goldfish feeding? Tell us in the comments!

          Complete Guide on Goldfish Food and Feeding. What Goldfish eat in the wild and what in captivity. What is the best food for goldfish you can give them and how often goldfish should eat.

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