There is a specific time when goldfish must chase each other. This is the spawning period. So if you find your pets going after each other when they are not in the breeding season, that is a sign that something is wrong.
Check out this article to find out why goldfish chase each other. You will also learn how to stop them from pursuing each other.
Why Are My Goldfish Chasing Each Other?
Male Goldfish Chasing Female Fish During Spawning Season
Goldfish are usually aggressive during the spawning season. During the mating season, male goldfish chase the females for several hours. You will notice the male goldfish chasing your female goldfish relentlessly, which is completely normal.
Chasing is a way of encouraging her to release her eggs during the mating season. The male fish follows her for hours after sensing she is ready to spawn.
In the end, the female will surrender and release her eggs. It is a tiring mating ritual. Sometimes, you can find the male nipping the fins and tail of the female as though they were fighting.
The chase usually ends when the female releases her eggs and the male fertilizes them. He releases his milt over the eggs to fertilize them.
You may notice that the water is cloudy when he fertilizes the eggs. This is pretty normal behavior. The cloudiness will disappear after a short while.
It may seem weird, but that is how they mate.
Overcrowded Tanks
You will often find goldfish pursuing each other in an overcrowded tank. Goldfish do not like an overcrowded aquarium. They need enough space to swim, mate, and do other things. It does not matter if you have had some success raising goldfish in small tanks.
There are many undesirable consequences of keeping goldfish in an overcrowded tank. Ideally, a goldfish needs at least ten gallons to live comfortably. This means that if you want to keep more goldfish, you must ensure that you have a bigger tank, especially if you keep them with other fish species.
If your tank is too small, your fish will become aggressive toward each other. Bigger fish may begin to go after and bully your smaller fish.
If you find your fish chasing each other, upgrading to a larger tank that can accommodate all the fish would be best. If you cannot get a bigger tank, you want to move some of the fish to a separate tank.
Health Challenges
In certain circumstances, sickness and injury are other reasons you may find one goldfish pursuing the other. Goldfish are cold-blooded animals, not only in the scientific sense but also literally. If you have an injured goldfish in the tank, it will become a target for other goldfish.
When healthy goldfish bully the weaker fish in your aquarium, the weaker fish will come under stress. This is another health issue that adds to the already existing health challenge of the weaker fish.
One of the main reasons for quarantining sick fish is to protect them from the aggressive nature of their tank mates. You can still protect your fish with a tank divider if you do not have a quarantine tank. It will offer the same protection.
However, there are some medications that need to be added to the tank water for treating sick fish. It would be best to seek veterinary advice to know whether the other tank mates will not be affected by the medication.
This is important because the tank divider will not bar the medication from reaching the healthy fish, whereas a quarantine tank will.
The Difference in the Appearance of One Fish From the Other Fish
You will notice that fancy goldfish have long and flowy fins, whereas common goldfish only have short and more defined fins. Usually, common goldfish chase them when you put them in the same aquarium.
As fin nippers, your common goldfish will naturally become attracted to their tank mates’ long and flowy fins. Because they do not have enormous tails and fins, common goldfish will swim faster than their tank mate.
Do not also be surprised when you see smaller goldfish chase and nibble at the flowy fins of the fancy goldfish too. But this can make them come under stress.
Competition During Feeding Time
Food is another reason goldfish chase each other. If you have an outdoor pond or have seen goldfish in the wild before, you would have noticed that they are always looking for something to eat.
If your pets chase each other when you feed them, the problem could be that you are not providing enough food. When you do not provide enough food, you create competition for food. Your pets will go after each other as much food as they can.
Always ensure that you offer enough food for everybody in the tank.
Territorial Behavior
The last reason you may find your pets chasing each other is because of territorial disputes. Goldfish claim territory to establish dominance and will fight any new fish you introduce.
If your pets have established dominance, they may feel threatened when you add a new fish to the tank. When this happens, the natural response is to bully the new addition, and chasing it is part of the tactics used.
The bullying usually stops after a while. But if it does not, you need to act fast to ensure that none of them gets injured.
How Can I Stop Goldfish From Chasing Eachother?
The first step would be to identify what the problem is. After identifying the problem, you will be better informed to stop them from chasing each other.
Here are a few tips to know what the problem is and how to correct it:
- If the reason is territory disputes, you can add more plants and other decorations to create more hiding places. This will limit the chances of confrontation because the bullied goldfish can find somewhere to hide.
- You can also separate the aggressive fish and reintroduce it later after it has calmed down.
- But if your tank is too small, the best option would be to get a larger aquarium that can accommodate all the fish.
- If your pets compete for food, you can increase the amount of food you feed them. Increasing the feeding time will not solve the problem because all your fish are always hungry. You need to provide enough food for them.
- You want to quickly move the fry to a separate tank when your eggs hatch. Separation is a good way to prevent overpopulation.
- Alternatively, you can reduce feeding if you do not wish to keep the fry. When you do, your pet will take care of the population problems themselves, and your water quality will remain pristine as you will not have uneaten foods rotting in the water.
- Pairing common goldfish with other fish that have long and flowy fins can prove to be a grave mistake. It would be best to keep only one type.
Do Goldfish Chase Eachother in the Pond
It is rare to find goldfish pursuing each other in an outdoor pond. The pond is very similar to its natural habitat. There is an abundance of natural food for everyone to eat, enough space for everyone to move around, and many hiding places to escape bullies.
There is also abundant room for every aggressive individual to carve his territory. So the chances of fish pursuing each other are pretty minimal.
The only reason pond goldfish will chase each other in the pond is for mating. The males may seem aggressive during this time, chasing female fish for many hours. You will notice a lot of frantic movements in the pond. But after fertilization, everything will be back to normal.
Bottom Line
Understanding the behavior of your pets is necessary if you want to prevent them from going after each other.
Knowing how they behave normally when males and females mate and many other things about them help you make the right decision when you see unusual behavior.
At Aquarium Labs, she's dedicated to assisting more people discover pleasure in fishkeeping and teaching them how to develop into expert pet parents.