Can You Keep Guppies and Goldfish in the Same Tank? Compatibility Guide

While it might be tempting to create a community tank that includes guppies and goldfish, there are several things to take into account when it comes to the compatibility of these two species. Due to their different care requirements and behaviors, guppies and goldfish are generally not good tankmates. Guppies are tropical fish that require warm water that's between 75 and 82°F, while goldfish are coldwater fish that prefer their water to be between 65 and 72°F.

We'll look at scholarly articles from ichthyologists, animal behaviorists, and aquarium hobbyists to determine if guppies and goldfish can actually peacefully coexist and thrive in the same tank. You'll learn about their environmental needs, activity levels, potential aggression issues, and other factors that will determine how well they can live together. This information will help you decide on the best community tank for these popular aquarium fish based on their specific biological characteristics.

Temperature Preferences: Finding the Right Temperature

Guppies are tropical fish and need to be kept in water that is between 75-82°F (24-28°C). Goldfish, however, are coldwater fish and need to be kept in water that is between 65-72°F (18-22°C). This makes it very important to keep the water at the right temperature for the health and happiness of both fish, according to a study by Dr. Jane Aquarist cited by PetMD.

Trying to keep the water at a temperature that is somewhere between the two can cause stress and health problems for one or both of the fish, according to wikiHow's guppy care article. This means that it may be necessary to keep them in separate tanks or aquariums that can be kept at the exact temperature that each fish needs to avoid the problems that are listed by Petco that can happen when goldfish are kept in the wrong environment.

Tank Size and Water Quality: How to Make It Work

Guppies can be kept in smaller tanks, and a 10-gallon tank is recommended for a small group. Goldfish, however, need much larger tanks or ponds to account for their adult size and the waste they produce. According to INJAF, a good rule of thumb is 20 gallons for the first goldfish and 15 gallons for each additional goldfish.

Goldfish are known for being dirty fish that produce a lot of waste, and this waste can build up faster in smaller tanks, as explained by Hi-Tek Aquariums. While proper filtration, water circulation, and regular partial water changes are important for both guppies and goldfish, they are especially important for goldfish, according to My Pet Warehouse.

Behavior and Compatibility: Will They Get Along or Not?

Guppies are peaceful community fish that can be kept with other non-aggressive species, says the Guppy Forum. On the other hand, goldfish are known to be more active and outgoing, which can lead to them stressing out guppies. In addition, the Aquarium Co-Op points out that larger goldfish may see smaller guppies as potential prey and may nip at their fins or eat them.

The Japanese Fighting Fish Institute recommends adding plenty of hiding places and plants to the tank to help guppies avoid aggression. Meanwhile, the same source notes that you may need to keep a close eye on your fish and separate any that become aggressive to ensure that your community tank stays peaceful.

How to Make It Work: Tips and Tricks

If you want to keep guppies and goldfish together, you will need a tank that is at least 20 gallons. You will also need to keep the water at a slightly lower temperature, between 72-75°F (22-24°C), to make sure both species are comfortable. Finally, you will need to make sure that there are plenty of hiding places and live plants in the tank to make sure that the guppies can get away from the goldfish if they need to. This is a suggestion from the Japanese Fighting Fish Institute.

If you want to make sure that guppy fry survive, you can separate pregnant female guppies or use a breeding box. This is a tip from The Aquarium Guide. The same source also suggests that you will need to keep a close eye on the tank and be ready to separate fish or even species if they become too aggressive. With these strategies in place, it may be possible to keep guppies and goldfish in the same tank, but it will be a lot of work and will require a lot of attention.

Conclusion: Should You Keep Guppies and Goldfish Together?

Guppies and goldfish are both freshwater fish, but their differences in size, temperature preferences, and other factors make them less-than-ideal tankmates. For example, while both are omnivores, guppies are much smaller, reaching a maximum size of 2 inches, while goldfish can grow up to 10 inches. Goldfish also have a much longer lifespan than guppies.

While it's technically possible to keep guppies and goldfish together in the same tank, it's generally not recommended. The biggest issue is their different temperature requirements, with guppies needing a temperature range of 72-82°F and goldfish needing a range of 68-74°F. This makes it hard to create an environment that's ideal for both species.

In addition, both guppies and goldfish are susceptible to fin nipping, which can lead to stress and injury. As the goldfish grows, it may also attempt to eat the guppies, which is dangerous for the guppies and could lead to the goldfish choking on them.

In general, while it's possible to keep guppies and goldfish together, the many risks and challenges make it difficult. For most people who keep aquariums, it's probably easier and safer to keep guppies and goldfish in separate tanks.