Pet Keen is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Home > Goldfish > Do Goldfish Feel Alone? How to Introduce a New Tank Mate

Do Goldfish Feel Alone? How to Introduce a New Tank Mate

feeder goldfish

It’s not unusual to spot a goldfish living alone in a tank. Many people get goldfish as a prize or as a gift for their child, which usually means they just have one goldfish. Sometimes when you see a singular goldfish, it may seem kind of down and depressed. It may not be particularly active, or you may notice its fins drooping, or it may just seem overall down and depressed.

How can you tell if a goldfish is lonely? Do goldfish even get lonely? The short answer to this question is “no”. Keep reading as we look at this in more detail.


Does My Goldfish Need a Friend?

Goldfish are not shoaling fish, so they don’t need to live with other goldfish to feel safe or happy. In the wild, they may live in the presence of other goldfish, but they don’t rely on other goldfish for safety or to get food. In fact, in the wild, goldfish only rely on other goldfish for reproductive purposes. Once spawning has occurred, the parents do not provide any care for the eggs or the fry, so these fish are alone from day one.

While we can never know for sure, there is no indication that goldfish get lonely. It’s likely that when you spot a single goldfish that seems lethargic or depressed, it is far more likely that there is a problem with its environment or health than it is that the goldfish is lonely. Infections, parasites, and inappropriate water parameters can lead to signs like clamped fins, lethargy, and general depression.

alone goldfish
Image Credit: 1980supra, Pixabay


Will My Goldfish Enjoy Having a Friend?

Even though goldfish aren’t shoaling fish, they are social fish. This makes them great additions to some community tanks, especially with other goldfish. Goldfish will eat almost anything they can fit into their mouth, though, so goldfish do not make good tank makes to fish and invertebrates that are small enough to be eaten, like tetras and dwarf shrimp.

Since goldfish are social fish, many of them will happily live aside other fish, even though it’s not usually a requirement for their health or happiness. If you want to get your goldfish a tank mate, then get a tank mate unless your goldfish has a history of bullying and fin nipping. If you don’t get your goldfish a tank mate, they won’t know the difference. While goldfish are more intelligent than they are often given credit for, they are not able to understand the concept of loneliness.

If your goldfish has had a tank mate for a long time that has recently passed away, then your goldfish may exhibit symptoms that indicate depression or grief. If your goldfish is accustomed to having a tank mate and they have lost that tank mate, a new tank mate may help your goldfish’s environment feel more normal and routine.

Image credit: Waraphornapha, Shutterstock


How to Introduce a New Tank Mate

The first thing you should do when you bring home a new tank mate for your goldfish is to go through with a quarantine protocol. This should last anywhere from 2–8 weeks and helps ensure you are not introducing pathogens or parasites into your tank. Once the quarantine period is complete, you’re ready to introduce your goldfish’s new friend.

If you're new to the world of goldfish keeping or are experienced but love to learn more, we highly recommend you check out the best-selling book, The Truth About Goldfish, on Amazon.The Truth About Goldfish New Edition

From diagnosing illnesses and providing correct treatments to proper nutrition, tank maintenance and water quality advice, this book will help you to ensure your goldfish are happy and to be the best goldfish keeper you can be.

You will need to acclimate the new tank mate to the main tank by floating the new fish in a bag to help it adjust to the temperature of the tank. Once you’ve acclimated the new fish, you’ll release it into the tank. It may take a few days for your goldfish to adjust to a new tank mate. Goldfish tend to be curious, though, so it will likely investigate its new tank mate shortly after the addition.

lion head goldfish in an aquarium
Image Credit: Tina Designs, Pixabay


Breeding or Bullying?

It’s not uncommon to spot your goldfish chasing other goldfish tank mates, especially new ones. Sometimes, this is just an adjustment period that only lasts a couple of days. You can use tank dividers or a breeder box to help make sure nobody gets injured during this adjustment period.

If you spot fin nipping or any injuries beginning to occur, you should separate the fish. This is indicative of bullying. If you’re seeing chasing and nipping at the lower abdomen, it’s likely that you’re witnessing breeding behavior. Male goldfish will do this to encourage females to release eggs for spawning. You can help this process go more quickly by gently squeezing your female fish to help her release the eggs. Don’t do this if you feel you might injure your goldfish.


Final Thoughts

Your goldfish likely doesn’t need a tank mate, but they appreciate the company. It can be fun to watch goldfish interact with each other. Sometimes they will just spend time together and other times, they may live completely separate lives within the tank. Make sure to keep everyone safe by sticking to slow introductions following a quarantine period.

If you notice bullying or injuries occurring and the behavior does not begin to decrease, you may need to consider rehoming the new fish to prevent stress.

You May Also Like:

Featured Image Credit: Juan Carlos Palau Diaz, Shutterstock

Our vets

Want to talk to a vet online?

Whether you have concerns about your dog, cat, or other pet, trained vets have the answers!

Our vets