Do Goldfish Eat Other Fish? How To Prevent It From Happening?

do goldfish eat other fish
Do goldfish eat other fish? Well, this can be the first question flash on your mind when you introduce other fish into the goldfish aquarium tank.
Whether you are a newbie or an experienced aquarist, you would want to consider fish’s temperament while keeping them in your community tank. You would not want your aqua pets to fight and gobble one another. As an aquarist, you would like to prevent it from happening; thus, you would learn to avoid the goldfish eating other fish by learning thoroughly, goldfish temperament.
Goldfish keeping is an expensive and time-consuming hobby; especially, to keep them in a community tank; sometimes, it might vex you to find some specimens missing in your goldfish community tank. However, you most definitely prevent it or minimize it from happening by following a few guidelines in goldfish keeping.
After reading this article, you can stop bombarding yourself with questions like, do goldfish eat other fish? Or do goldfish eat each other?

Are Goldfish Predatory in Nature?

Goldfish are omnivores; they eat anything that fits in their mouth indiscriminately; they won’t play favoritism from their tank mates to their meals. 

However, goldfish are very generous and kind, unlike the other rigorous predatory species like cichlids, Oscars, rainbow sharks, tiger barbs, pufferfish, etc. They do not chase other fish to eat them up.

But, in the wild, your pet goldfish is not just predatory. They are considered one of the worst invasive species; because goldfish continue to grow as much as their resources permit till their death. Goldfish continue to release growth-inhibiting hormones; in your aquarium tank or a bowl, the concentration of these hormones keeps their size limiting to their habitat. 

But in the lakes, streams, it is an entirely different story; the growth-inhibiting hormones are diluted in the massive water body permits them to grow without any check. 

Do not forget goldfish are eating machines; they do not stop eating on their own accord; hence, they munch on plants, crustaceans, and other fish in the lakes and the other water streams without any limits creating a scarcity of food and resources for the other native species. 

Releasing your pet goldfish into the neighborhood lakes, ponds, or any water streams can cause massive damage to the ecosystem.

Are Goldfish Cannibals?

Cannibalism is a rare occurrence among the goldfish. Generally, goldfish are neither aggressive nor territorial by nature; however, cramped space can stress them and stress not healthy to any fish; when you house too many goldfish in a small tank, one or two goldfish might create a starvation situation for the rest of them by bullying.

Goldfish are opportunists; they eat anything that fits in their mouth while grazing; that fit happens to be a small goldfish, it will eat them without any prejudice.

Like most fish species, goldfish do not parent their offsprings; they lay hundreds of eggs; if you don’t have a separate breeding tank, the goldfish will consume the eggs indiscriminately; the eggs that manage to survive and hatch will live uncertain lives till they reach large enough not to fit in the mouth of adult goldfish or other species.


Do Goldfish Eat Other Fish?

The truth is that even the full-grown large goldfish are not that aggressive or predatory by nature. On the contrary, goldfish are active fish but slow except during the feeding time; hence, they do not chase prey; nonetheless, when they are hungry, which is always; if they come across small fish that fit into their mouth and devour them up. 

Also, they eat plant matters; that is why you would want to use only hardy plants such as Java fern, Crinum, Anubias, etc., in your goldfish tank.

However, the scenario can become different at times. For example, baby goldfish can sometimes swallow other small fish that easily fit into their mouth. You cannot consider this as aggressive behavior or an intended action; it is pretty evident for an omnivorous fish that is immensely hungry and looking for food. However, if you deliver them food consistently, it will keep them from eating other tiny fishes.

Also, sometimes, the baby goldfish do it mistakenly; they often search for food in different tank regions; and if any small fish passes through that quarter and comes in front of them, the goldies do not discern them differently from their meals. 

But this is entirely unintentional and mistakenly done! It’s not an outcome of their aggressiveness. Just ensure you are not keeping them with much smaller fishes that fit into their mouth. Also, by doing this, you can prevent them from committing such mistakes and need not even have to worry about your goldfish eating up other tiny fishes. 


Do Goldfish Eat Their Babies?

It can be a genuine concern for you if you are thinking of breeding goldfish in your home aquarium! Well, sometimes goldfish do become rude enough to eat up their babies, but isn’t it typical of most fish species?

Mostly, goldfish end up producing hundreds of eggs at a time, which they eat up occasionally. Also, they can eat away their fries. But as we know, goldfishes aren’t aggressive or predatory, so what makes them indifferent to their babies? 

Well, that’s because goldfish lack parental instincts; consequently, they fail to discern their babies from their meal. Hence, there are higher possibilities that the mommy and daddy fishes will eat away their babies if you keep them in the same tank. So, if you want to breed them, separate the parent fishes right after the eggs are spawned.

Besides, some studies also show that apart from their eggs and babies, goldfishes also tend to eat up the eggs and larvae produced by other aquatic animals in the tank. However, devouring the fish eggs is not unique to goldfish, but it is a common trait among most fish species. So, whenever any of your aquarium pets are about to spawn, transfer them to a separate breeding tank and provide them the utmost care.


Why Do Goldfish Eat their Tankmates?

The simple answer to this is that they love eating all the time; they eat plant and animal matter. Goldfishes, don’t give it a thought! So, any meaty substances, including their baby, or a dead fish, these hungry little monsters will relish them.
Goldfish are neither predatory nor territorial; however, they can get aggressive and attack other fish in certain circumstances. Therefore, when you notice any bullying and chasing, you would want to address the cause promptly if you do not wish to disrupt the harmony of the aquarium tank.
Most surprisingly, goldfishes can even gulp larger fishes in a tank. However, it’s a rare occurrence and an outcome of their frustration. After all, who wants to share their personal space? Neither you and me nor the goldfishes. Fair enough! Goldfishes require their own space; thus, they tend to show some aggression when it gets crowded.
Many fish owners can also notice a slightly aggressive behavior in their goldfish when introducing other new fish species into their habitat. However, when it is already crowded, the lives of the new arrivals of the tank are at stake.
When goldfish notice a sick or injured fish, they immediately gang up against that specimen to pre-empt any calamity or pandemic in the community.  As an aquarist, if a fish seems weak or injured or an aquatic creature lays eggs in the tank, move the specimen immediately to a separate tank and nurture; otherwise, your goldfishes will feast on them.
Every so often, what you may perceive as aggressive behavior might be an exhibition of simple mating rituals; it is not unique to goldfish; most fish species exhibit aggressive mating behavior, even the much docile species.
As we know, goldfish eat continuously and therefore produce a massive bio-waste; hence maintaining water quality even with filtration can be challenging; dirty water can crumble the otherwise calm and peaceful disposition of goldfish.

How to stop goldfish from eating or attacking other fish?

Do goldfish eat other fish? Yes, despite their non-aggressive nature, goldfish end up eating their fellow tank mates at times. Now, let us see how to prevent goldfish from eating or attacking their tank mates.


goldfish space

Whether it is goldfish or any other fish in your tank, space is the principal criterion of all. When they live in a constrained space, they are likely to exhibit aggression towards other fish, especially to the weaker ones.

Thus, you would want to ensure that you give them enough space to move and swim around freely. The thumb rule is a gallon (approx. 4 liters) of water for every inch (2.54 cms) of goldfish. Remember, you would want to enlarge their habitat in accordance with the goldfish growth rate. 

Adequate food

Goldfish are omnivores; they feed on both plant and animal matters. In addition, they are opportunistic eaters; hence eat anything planktons, zooplankton, aquatic plants, invertebrates, small fish, worms, larvae, snails, etc.

In the home aquariums, goldfish mostly thrive on commercial flakes and pellets, depending on the fishkeeper. However, goldfish need much more than commercial flakes and pellets to thrive and live healthily. You would want to feed them some blanched veggies such as spinach, peas, zucchini, kale, carrots, cucumbers, etc. 

Remember, never feed your aquarium fish unblanched veggies, not boiled veggies. Store-bought vegetables may contain chemical pesticides and insecticides, which can damage the aquarium water chemistry that could damage your fish fins, scales, and sometimes internal organs, and eventually, it can even kill your fish. Additionally, decomposing veggies can add loads to your nitrogenous bacterias.

In addition, from time to time, some live treats such as Daphnia, Brine shrimp, Bloodworms, Shrimps, etc., are essential to keep them thriving.

To prevent goldfish from eating other fish, follow a strict feeding schedule; goldfish do not have stomach; through their digestive system, the nutrients are absorbed, and they look for food constantly and eat all the time; hence, it is wise to feed them few times in a day instead of one large meal.


Maintaining Aquarium water quality:

Goldfish soil a lot as they constantly eat. Maintaining a goldfish tank is an expensive hobby; it requires money, space, time, energy, and most of all, passion. Passion is the key to own a healthy goldfish aquarium tank!

Despite running filtration 24X7, routine water changes are required, weekly or twice a week, depending on the filtration and size of the tank in relation to the number of specimens. 

Testing and maintaining water parameters at its optimum level is a crucial part of goldfish keeping: a water temperature between 68° to 74° F(20° to 23° C), acidity 7 to 8pH, Hardness up to 12 dGH, carbonates, and bicarbonates 80 to 180 ppm; ammonia and nitrites at 0 and nitrates below 20 ppm.

Water quality plays determining role in the goldfish’s health and temperament. Good water quality, along with a good diet and space, keep the goldfish happy and vibrant. 

Live aquarium plants and other decors

Sometimes, all your goldfish requires is a better tank to live in. Therefore, add more live plants and rocks; and the decors like caves, tubes, shells, etc.   

Goldfish are more herbivores than carnivores; they love munching on aquatic plants and algae; hence, choosing live plants for goldfish tank, choose hardy ones such as Java fern, Anubias, Ludwigia Repens red aquarium plants, etc.

These live aquarium plants absorb excess nitrates and other water impurities, thereby reducing the burden on nitrogenous bacteria and filtration; it improves oxygen levels in the water and shelters small and weaker fish.

Cure the injured or sick fish

Goldfishes do not like the weaker or injured fish in their habitat. So, if a fish gets injured or falls sick, move the fish to a breeder’s box. My suggestion is to keep them in a separate small tank, in case the ill or injured fish is infected with some diseases, it prevents the infection or disease from spreading to other inmates in the habitat; if I remind you, that is one of the reasons for goldfish attacking or eating their tank mate.

Keep the fish in a separate nursing tank during its entire curing period, and once recovered, move it back to the main aquarium tank.

Separate the aggressor 

If you have more than one goldfish in your tank, and one of them is more aggressive than the others, then there is nothing you can do about it except separate the aggressor from the rest of the inmates; no amount of food or space or hiding spots would stop the aggressor.

Also, if you have a large aquarium, you can easily offer the aggressor ample space by demarcating their territories in the same tank using a plexiglass separator. 

Choose the ideal inmates:

By and large, goldfish are not mean or aggressive fish; they are just an eating machine that eats anything edible that fits in their mouth. Hence, choose fish species that won’t fit in the adult goldfish mouth with a peaceful demeanor like platies.

If you like to keep small colorful fish with goldfish, you would want to choose the swift and agile species such as White cloud mountain minnows, Celestial pearl danios, etc.

You would want to avoid some small fish species such as neon tetras, which are fin nippers, especially if you have a long-tailed goldfish or any other fancy goldfish. However, if you still want to keep tetras with your goldfish, Ember tetras, cardinal tetras are an excellent choice.

A warning, despite the swiftness of these small fish species and hiding spots, every once in a while, you might see some missing specimens.


Related readings:

Can guppies live with goldfish?

Parting Thoughts – Do goldfish eat other fish?

Goldfish are not predatory by nature; they are simple creatures that need to eat all the time. So while browsing for the food, anything edible that fits in their mouth becomes their meal that includes their babies too; there is nothing mean about it.

Do goldfish eat other fish? Despite them gulping down their inmates, goldfish are considered to be a peaceful fish species. For the most part, they don’t go around bullying or fin nipping; on the contrary, they can be the victim of most fin nippers, especially the fancy goldfish types.

So, if you ensure to offer them adequate space and a properly balanced diet in a clean habitat, it should be sufficient to take care to retain their peaceful demeanor.

Related questions:

Do Goldfish Eat Dead Fish?

Well, yes, when a fish dies in the aquarium, there are higher probabilities that your goldfish will eat it up to remove it from their territory.

You may not even get to know that a fish was dead in your tank, as the goldfish will start eating it up right away. They are almost always hungry. So, whenever they get such a snack in front of them, they will undoubtedly try to gobble it at once.

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