Best Tank Mates for Goldfish

goldfish in a tank

boonchai wedmakawand / Getty Images

Goldfish are one of the best beginner fish. They are personable, interactive, and hardy enough to put up with a lot of beginner mistakes. However, once you've mastered their care, perhaps your goldfish might like a suitable friend. The biggest obstacle is choosing fish that do not require tropical temperatures, have easy going personalities, and can hold their own during feeding time.

Goldfish Are Generally Okay by Themselves

Some goldfish just don't like having any company. Especially for fish that have been on their own for over a year, adding a new tank mate can be a scary and intimidating ordeal, resulting in aggressive or bullying behavior. This behavior may show as nipping, aggressive swimming and restricting access to food at feeding time.

Goldfish are just fine being by themselves. They enjoy interacting with their caregivers and are not suffering from lack of company. "Only child" goldfish can benefit from additional interaction with multiple family members or varying their tank decor. You can even train them to do tricks!

However, goldfish do work well with a few other fish species and can benefit from the company. Here are some of the best options for goldfish tank buddies:

  • 01 of 04

    Another Goldfish (Carassius auratus)

    Goldfish swimming in tank

    HowardOates / E+ / Getty Images

    Goldfish like swimming with other goldfish (no profile). Standard comet goldfish should be kept with other comets with fancy goldfish (no profile) kept with other fancies. Fancy goldfish lack the mobility and maneuvering that can be a problem during feeding time. Comet, sarasa and shubunkin varieties have similar body types, but different coloration if you are interested in variation.

    Comet goldfish, even though they start cute and small, can grow up to the size of a dinner plate (12") if kept in the right conditions. Trying to limit your fish's size by keeping them in a tiny tank or restricting their diet will only stunt them both structurally and immunologically. Healthy goldfish thrive by having lots of room to swim. So, no matter the type of goldfish, you will need at minimum 20 gallons per fish.

    All goldfish should be on a goldfish-specific pelleted diet. To combat over-eating at the surface resulting in a positive buoyancy disorder, it is better to keep most fancy varieties on a sinking pellet. If you have overly-competitive fish in the same tank, try to spread out the diet over then entire tank surface or mix floating and sinking pellets.

  • 02 of 04

    Zebrafish (Danio rerio)

    Zebra fish

    isoft / Getty Images


    Zebrafish are peaceful, tiny fish that like to swim in groups. They may start out at about one inch in length and max out close to two inches, making them significantly smaller than most types of goldfish. Due to their different body size, they can be combined with both comet and fancy varieties of goldfish.

    They come in a variety of colors and fin lengths. Make sure to start with a size that is bigger than your goldfish's mouth! Although they may not intentionally eat them, if a fish accidentally gets in the way during feeding time, they will be swallowed.

    Zebrafish are usually too small to eat standard goldfish pellets. Although you may be tempted to use flake, smaller tropical fish pellets are best. Flakes loose too much nutrition too quickly, due to a high surface-to-mass ratio. By varying the diet in your tank, you will limit the amount of competition between species.

  • 03 of 04

    Ornamental Minnows

    White cloud minnow

     Besjunior / Getty Images

    There are many varieties of minnows that are suited for ornamental tanks. Being cousins of the zebrafish, they have similar taste in food and care. Just like the zebrafish, they like to swim in groups, so you may have to start with three or more. They are similar in size to zebrafish when they grow to their max size.


    Fish should never be taken from the wild and kept in artificial systems, especially if you are adding them to a tank with fish already in it! Wild fish tend to have lots of bacteria and parasites that can quickly jump to other fish.

    Some more common varieties include the rosy red and white cloud. Different varieties have their own standard colors, but the care is identical.

  • 04 of 04

    Nerite Snail (Neritina sp.)

    Nertite snail cleaning the side of an aquarium

     Alexandra Marin / Getty Images

    Unfortunately, non-tropical freshwater ornamental species are limited, but you can also consider invertebrates, such as the Nerite snail. These fastidious scavengers can help keep your tank clean by nibbling on detritus and algae.

    These snails can grow up to one inch and come in a variety of shell colors. Most fish will usually leave them alone unless the snail happens upon a tasty tidbit a goldfish wants. Worst case, the snail gets launched off and has to go find another snack.

    The main concern about having snails in your tank is overpopulation. Happy, healthy snails will replicate very quickly. Being hermaphrodites, they don't need any help! Limiting snail food sources, such as excess food and algae, will help limit your population.

Keep in mind that any new tank additions should be quarantined for four to six weeks in a separate tank with separate equipment. This will keep any new bacteria and parasite from getting into your tank.

Be sure to watch your new additions once they are added to the new tank to make sure everyone is getting along. Not all goldfish like having friends. If your goldfish is nipping or chasing the new additions, try adding some more hiding places so everyone can have their own space.

Always assess your tank size before adding any more fish. Goldfish need 20 gallons minimum! Stunting them in a smaller tank will only hurt their immune function. If you are struggling to accommodate your current fish, you should not add any others.