Ering goldfish in one tank, a vibrant, colorful school of guppies in another

Guppies And Goldfish: Reasons To Keep Them In Separate Tanks

Do you have a tank that houses both guppies and goldfish? If so, you should be aware of the differences between these two species in order to keep them healthy and safe.

It’s important to understand why it’s best to keep them in separate tanks, from their water requirements to temperatures they prefer.

In this article, you’ll learn about all the reasons guppies and goldfish should not share a tank.

Key Takeaways

  • Goldfish and guppies have different water requirements, including temperature and oxygen levels, which can be best met by keeping them in separate tanks.
  • Separate tanks prevent food competition between goldfish and guppies, as well as the issue of overfeeding when goldfish have higher stocking levels.
  • Territorial behavior can occur between guppies and goldfish, so keeping them in separate tanks ensures freedom to explore without fear of being chased or attacked.
  • Guppies and goldfish have different breeding behaviors, with guppies being more prolific breeders and goldfish having longer breeding cycles. Separate tanks allow for natural breeding behaviors to occur.

Different Water Requirements

Goldfish require colder water than guppies, so it’s best to keep them in separate tanks. This is especially important if you’re breeding them since they have different temperature requirements.

Keeping them apart can also help prevent the spread of diseases between species.

Both fish types also possess different nutritional needs, which further necessitates keeping them apart for optimal health and freedom.

Competing for Food

You should house guppies and goldfish in different tanks, as they compete for food.

Goldfish have higher stocking levels than guppies, which can lead to overfeeding when kept together.

Goldfish are also omnivorous and may consume the same food as guppies, leading to competition between the two species for food.

Guppies tend to be more active feeders than goldfish so they could out compete their tank mates if not given adequate feeding habits.

Keeping them in separate tanks allows them both to thrive without competition for resources.

Territorial Behavior

Therefore, it’s important to consider their territorial behavior when deciding whether to keep them in the same tank. Guppies and goldfish can be highly social creatures, but they may still compete for territory within a tank. This is especially true if there isn’t enough space or resources for both species.

If their differences in size and speed are taken into account when considering tank size, then social interactions between the two species may be avoided. However, it is generally recommended that guppies and goldfish are kept in separate tanks to ensure everyone enjoys freedom to explore without fear of being chased away or attacked by the other species.

Different Temperature Preferences

It’s important to consider the different temperature preferences of guppies and goldfish when deciding how to house them. Guppies prefer warmer water temperatures, while goldfish thrive in cooler temperatures. Temperature fluctuations can cause stress to both species, which can lead to health problems.

Keeping guppies and goldfish in separate tanks ensures optimal oxygen levels as well as proper temperature range for each species. Providing the right environment is key to keeping these fish healthy and happy!

Different Breeding Habits

Guppies and goldfish differ in their breeding habits. Guppies are more prolific breeders than goldfish. They are known for having multiple broods over short periods of time. In contrast, goldfish have longer breeding cycles.

Guppies also form social groupings amongst each other when searching for mates. On the other hand, goldfish tend to be solitary during the spawning process.

Keeping these two species separated allows each to follow their natural breeding behaviors without interference from the other.

Potential Health Risks

Keeping these two species apart is important, as mixing them can cause health risks to both. Poor water quality due to overcrowding and disease spread can lead to illness or death in either species.

Preventative measures include regular tank maintenance and monitoring of water parameters. To reduce the risk of infection, keep separate tanks for guppies and goldfish. Doing so will ensure optimal water conditions for each species, maximizing their potential for a healthy life.

Frequently Asked Questions

What size tank should I keep for guppies and goldfish?

When buying tanks for guppies and goldfish, consider their tankmates compatibility. A 10 gallon tank is suitable for a few small guppies, but you’ll need a 20-30 gallon tank for larger goldfish. Be sure to provide plenty of space and choose compatible species that won’t harm each other.

What type of filter system is best for guppies and goldfish?

For guppies and goldfish, an active filtration system is best. This ensures a constant water temperature and cleanliness for both species. Choose one that works with your tank size, budget, and desired level of maintenance. You’ll be rewarded with healthy fish!

What type of food should I give to guppies and goldfish?

When choosing food for guppies and goldfish, you should consider their individual feeding habits. Guppies prefer a flake or pellet food while goldfish opt for sinking pellets. Both also benefit from frozen, live, and vegetable-based foods. Be sure to feed them in moderation to ensure a healthy diet!

How often should I change the water in the tanks?

You should change the water in both tanks every 2-4 weeks to ensure optimal breeding behavior and tank mate compatibility. It’s important for water quality and fish health.

What type of decorations should I put in the tanks for guppies and goldfish?

You should choose gravel based on the size of your fish. For guppies, small-grained gravel is best. Goldfish require larger grains for their delicate scales. Additionally, both species need live plants that provide hiding and spawning places; Java Moss and Anubias are two good plant types to use.


You’ve seen the reasons why it’s best to keep guppies and goldfish in separate tanks. With different water requirements, competition for food, territorial behavior, temperature preferences, and breeding habits, it makes sense to house them separately.

Not only will they both be healthier and happier this way, but you won’t have to worry about potential health risks associated with keeping them together.

Separating your fish into two different tanks is a smart choice that will pay off in the long run!



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