Goldfish and guppies both have their own charms. Both fish have big personalities and can be both soothing and entertaining to watch. Since they both bring their own unique beauty to tanks, you may have wondered if you can house goldfish and guppies together. With some planning and consideration, it is possible to keep guppies and goldfish in a tank together.

Keep reading to learn what works and what you need to avoid with this setup.

What Makes These Two Fish Good Tank Mates?

You may have heard guppies referred to as tropical fish and goldfish as cold-water fish. Both of these are kind of accurate, but not 100% true. Goldfish prefer cool to temperate water and they tend to be happiest in water temperatures from 68–75˚F, so they are not true cold-water fish.

Guppies, on the other hand, prefer water from 72–78˚F, so their water preference is temperate to tropical. There is overlap between these two ranges, though, so you can find a tank temperature that is both safe and comfortable for both guppies and goldfish.

Due to the unique aesthetic of both types of fish, goldfish and guppies can both bring beauty and interest to your tank. Guppies are available in a wide range of colors and patterns, especially male guppies. Goldfish tend to come in slightly less interesting patterns than guppies, but they can have specially bred body or head shapes, colors, fin lengths, and even eye shape. The chubby bodies of fancy goldfish can make be a nice contrast to the colorful guppies darting around the tank.

Both fish also happily eat pests, like mosquito larvae and hydra, and rapid reproducers, like bladder and ramshorn snails. The size different in goldfish and guppies may mean that different pests are being eaten by both fish. For example, guppies won’t take care of your bladder snail infestation and goldfish are unlikely to take care of your hydra problem. Combining the two in environments where pests are present may lead to a healthy balance when it comes to keeping pest populations under control.

Another benefit of guppies, specifically, is that they eat algae and biofilm, both of which are things that goldfish don’t usually eat. This means that guppies can help clean up things within the tank, like driftwood, that goldfish won’t clean up. In some tanks, dwarf shrimp and certain varieties of small catfish perform these tasks well, but goldfish will usually eat these tank mates. This makes guppies a good alternative that is less likely to be eaten.

What Makes These Two Fish Poor Tank Mates?

Goldfish will eat just about anything, and that includes tank mates! They are peaceful fish, but they just really love to eat! If it fits in a goldfish’s mouth, it’s up for grabs. If your goldfish are still young, then they are likely too small to eat adult guppies. However, most goldfish are not too small to eat guppy fry. Guppies are livebearers, so happy guppies reproduce like crazy. If you’re okay with guppy fry being eaten, then this might not deter you.

Keep in mind that goldfish can get quite large, while guppies usually reach between 1.5–2.5 inches at the most. This means that if your goldfish and guppies are similar sizes when you get them, within a year or two, your goldfish may far outsize your guppies. Goldfish are social, but they don’t form the kinds of bonds with tank mates that will prevent them from eating their tank mates if given the opportunity.

How Can I Keep Guppies and Goldfish Together?

If you’re interested in keeping guppies and goldfish in the same tank, there are a few things you should consider.

First, if you want your guppies to be able to reproduce, you should either choose to keep these two species separate or provide heavily planted areas in the tank that allow for fry to safely hide out while they grow. Without plenty of heavy cover, you are unlikely to have any fry survive being kept with goldfish. Consider floating plants with trailing roots, like dwarf water lettuce and Amazon frogbit, and tall plants that can be grown in clumps, like Vallisneria, Ludwigia, and Elodea.

Secondly, be prepared to split your guppies and goldfish into separate tanks or make use of a tank divider once your goldfish begin to become large enough to eat your adult guppies. If you feel like you’re ok with some of your guppies being eaten, please consider that goldfish’s eyes are often bigger than their “stomachs”. This can lead to goldfish attempting to eat things that can choke them, which can lead to the death of both your goldfish and the guppy it attempted to eat.

Third, closely monitor your tank temperature and water parameters to ensure everything stays within a safe, healthy range for both fish. While guppies are not truly tropical fish and goldfish are not truly cold-water fish, both fish can suffer negative health consequences if kept in inappropriate tank environments. Aim to keep your tank in the low to mid 70˚F range if you intend to keep these two types of fish together.

Lastly, the ideal combination of guppies and goldfish is keeping your guppies in a tank with fancy goldfish. Most fancy goldfish tend to be slower than common-type goldfish, which means they are less likely to be able to catch fast-moving guppies or guppy fry. Fancy goldfish are often bred for looks, which can leave them at dexterity and coordination disadvantages, which can be a benefit when kept in a tank with guppies.

Summary

Contrary to what you might have heard, it’s not impossible to keep guppies and goldfish in a tank together while keeping both species happy and healthy. It does take planning and careful consideration, though! Goldfish can be difficult tank mates to small fish, and guppies can reproduce at a ridiculous rate, overtaking a tank in just a few months. Both fish may be able to balance the other out effectively, but it will still take work on your end to ensure the environment is safe for both types of fish.

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.

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.

Featured Image Credit: Tony Stock, Shutterstock