Do Goldfish Kiss Each Other?

Disclosure: I may earn a commission when you purchase through my affiliate links. As an Amazon Associate I earn from qualifying purchases. – read more

Keeping one goldfish versus several in the same environment comes with several core differences. The most notable one relates to the goldfish’s social behavior, which can perplex inexperienced aquarists. One of such odd behavior is the goldfish kissing each other.

But can we actually describe their behavior as kissing, and what does it mean? In short, goldfish don’t kiss in the true sense of the word, the one that we use to describe the human act. They don’t use the gesture to express love or affection, so the notion of ‘kissing’ isn’t really appropriate for describing the act.

But we’ll use it anyway since there’s no better word for it. So, why do they do it?

Why Do Goldfish Kiss Each Other?

There are 2 reasons why goldfish kiss each other: in times of love and in times of war. So, let’s break those down, shall we?

– Mating

The mating process is quite exhausting among goldfish, primarily due to the female being extremely picky. The goldfish male is always ready to perform, but the female isn’t. Female goldfish always play hard-to-get, with the male’s persistence being the only determining factor here.

The male will pursue the female throughout the tank, poking at it, nipping at its fins, and even going lip-to-lip. The goal is to wear out the female’s strength and drain its stamina, forcing it into submission. The underlying goal is to force the female to release the eggs.

In some cases, the male will poke the female’s abdomen or squeeze it against a hard surface (the tank’s wall or a rock) which will have the same result. The female will release the eggs into the water, the male will fertilize them, then the fish will go on with their lives.

So, if you see your goldfish ‘kissing’ each other, monitor their other behaviors as well. If the male keeps chasing the female and poking at it relentlessly, you now know why.

– Fighting

The fighting aspect is worthy of mentioning in relation to goldfish. That’s because goldfish are generally peaceful, so people don’t really expect to see them fighting. When they do, they don’t know how to react.

Before learning how to deal with goldfish violence, you must first learn how to identify it. Goldfish will exhibit a variety of combat-specific behavior, such as poking, nipping at other fish’s fins, constant chasing, and even kissing. The act of kissing is an aggressive and dominant display, aiming to put the victim in its place.

Goldfish exhibit this behavior mostly in relation to fish belonging to other species. Otherwise, they are quite peaceful and won’t get into too much trouble. The problem is that goldfish are rather stressed by new fish coming into their environment. They need time to get accustomed to their presence and might be a bit more irritable at first.

You should always monitor your goldfish’s dynamics upon introducing new fish to their habitat. If violence does occur, you have several tools at your disposal to mitigate the situation. We’ll discuss these shortly.

How do You Know if Goldfish Are Mating or Fighting?

The distinction is rather difficult to make, but there are ways to get an accurate reading. You should pay attention to 2 main indicators:

  • The fish’s sex – If both fish are males, the mating theory goes out the window. The only reason goldfish males would interact with one another is to establish the necessary hierarchical dominance. They won’t fight too much so long as they have enough space and hiding areas to cover behind. But it will happen occasionally, especially during the mating season or when stressed or hungry.
  • The mating season – If the mating season is on and the kissing behavior occurs between a male and a female, they’re most likely mating. The female’s belly is another clear indicator in this sense. Females that are ready to mate will display larger bellies since they’re full with eggs. The male will sense the female’s hormones, announcing its sexual availability and triggering its mating senses.

When it comes to fighting, in particular, you should consider the kissing behavior to be a concerning social interaction. While your goldfish will fight despite all your efforts to prevent it, their aggressive interactions should be kept to a minimum. The fish may not be able to kill each other directly since they’re not biologically built for that, but there are some risks involved.

Fish stress is one relevant issue to mention since aggressors may bully the weaker males, causing their stress levels to spike. Some minor injuries may occur as well, which always come with the risk of secondary infections. These can be deadly in some cases.

So, how do you mitigate the fish’s aggression? Let’s see!

How to Stop Goldfish From Fighting?

Goldfish fighting isn’t too bloody in general, but it can come with gruesome results either way. Even minor injuries can become infected and kill the fish several days after the fact. So, it’s essential to have a good prevention plan in place to keep your goldfish aggression minimal.

You can do that by:

– Increasing the Tank’s Size

It’s important to remember that goldfish’s growth rate and maximum size depend very much on the available space. You want to keep them in larger environments to optimize their size and boost their quality of life. Consider at least 15 gallons for one fish and increase that value exponentially with each new goldfish coming into the picture.

Goldfish aren’t excessively territorial but will become violent if they feel overcrowded. Having more space available is always a plus since it allows goldfish to swim around to escape their aggressor(s). You may need 20-30 gallons for 2 goldfish, depending on their subspecies and temperament.

Goldfish have different personalities, and some may be more aggressive than others. You want to ensure sufficient space to mitigate their aggressive tendencies and craft a more stable habitat.

– Decorating the Tank Properly

This is a sensitive subject due to goldfish’s rather fluffy fins. They can easily get hurt in various decorations if they’re not safe. They also don’t require too many hiding spots since goldfish enjoy open waters to swim freely. That being said, some hiding areas will benefit them as they will provide protection and comfort.

Consider adding some larger decorations here and there and some plants to beautify their habitat and create some much-needed safe spaces. These are even more necessary in community setups where different fish species have to learn how to cohabitate.

Goldfish can sometimes get snappy towards their tankmates, especially during the mating season, when hungry, overcrowded, or simply annoyed. Don’t worry, though, they are quite peaceful and easy-going for the most part. But it doesn’t hurt to have some safety mechanisms in place to prevent any unnecessary aggression.

– Keeping the Tank Water Clean

Goldfish tend to be calmer and more comfortable in a properly maintained environment with clean waters and a well-oxygenated habitat. I recommend performing regular maintenance, especially since goldfish are known for being kind of messy. Change their water at least once per week, no more than 20% each time.

You should most definitely increase the frequency of the maintenance work, depending on the number of fish and how messy they are. Keeping goldfish in a clean, well-oxygenated, and healthy environment will also considerably boost its quality of life.

– Provide Proper Nutrition

This refers to both the quality of food and the adequate amount too. Most goldfish only require 2-3 feedings per day. This is enough to keep them calm and satiated.

However, the situation is a bit different in a community tank or when housing several goldfish. Such environments will spark food competition, no matter how much food is available. So, your task is to make sure all of the fish eat properly.

Goldfish males especially are known for enforcing strict hierarchies when feeding. If you notice your goldfish fighting over food too often, try to feed them in separately as much as possible.

You should also remember that goldfish have different personalities, so, ultimately, all prevention tactics could fail.

When that happens, removing the aggressor from the environment is key to reducing the violence and stabilizing the system.

Can Goldfish Kill Each Other?

No, goldfish cannot kill each other. At least, not directly. They have no teeth or other means of inflicting immediate death, but this doesn’t mean they can’t hurt each other.

The constant poking and nipping at each other’s fins will leave marks. Physical injuries will get infected, and the infection will kill the fish if untreated. Psychological issues deriving from constant fish stress can have an equally deadly outcome. Stressed fish showcase lower immune systems and are more prone to infections and illnesses.

You should always check your goldfish for signs of violence and do your best to mitigate their behavior.


Goldfish will kiss each other occasionally, and their behavior always means something. Assess their behavior, look for other signs of aggression, and take the appropriate measures to calm the situation.

You should be able to mitigate your goldfish’s aggression by referring to this article’s recommendations.

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.
Leave a Comment

Your email address will not be published. Required fields are marked *