Can Guppies Live with Goldfish?

When aquarium owners visit their local store, they see different fish in the same tanks. They all seem to be living in harmony; however, when they get home and try to obtain the same equilibrium, they run into issues. Water conditions between fish can be one key problem, yet there are others and this leads to the question:

Can guppies live with goldfish?  The answer to this is yes and no. To do so means there has to be some compromises to make sure both kinds of fish have the ideal environment. On many occasions, it can be a struggle, and it is safer not to mix these two kinds of fish.

Here, we will answer the question in more detail, and then you have a better chance of knowing if you wish to try to have both kinds of fish co-habit in your aquarium.

Tank Temperatures for Your Guppies and Goldfish

Once you learn the habitats these fish come from, you hit the first hurdle. Guppies are a tropical fish and like their water temperatures around 77 degrees fahrenheit. Most aquariums will already be set up with aquarium heaters to deliver temperatures in this range.

Goldfish, on the other hand, are generally fish that live in cooler waters. They are used to temperatures between 68 to 74 degrees fahrenheit.

The issue here is if you keep your goldfish in these warmer waters, they become uncomfortable, and their life expectancy drops. Guppies, when in cold water, can refuse to eat, and they are more prone to illness.

Water pH and How it Affects Fish

Owners may overlook this one thing, as they strive to have goldfish and guppies in the same tank. Goldfish do prefer their water to be on the acidic side. Guppies do like their water to be alkaline.

If you have both fish together, you do need to have water that is pH neutral at around seven. This can take lots of checking testing to make sure these levels are in order.

One thing worthy of noting here, if you don’t make frequent water changes, water does turn acidic.  

Fish Sizes Plays a Big Part

It is possible to find different kinds of goldfish; these can grow to lots of different sizes. Guppies have another name of “Million Fish,” and this comes from their ability to deliver too many fry that can grow and quickly overpopulate any aquarium.  Female guppies can give birth once per month if they are fertilized.

While you may see them in the store together, these are often of a similar size, yet once your goldfish begins to grow to maturity, and often up to ten inches in length, they overshadow the small guppies.

Goldfish are also omnivores so that they will eat both plants and meat. Guppy fry will be a tasty snack, and they will move onto eating adult fish once they consume all the fry.

Tank Maintenance and Filtration

If you have these fish in your aquarium, you will need to be prepared to change around 30% of your tank water every two weeks or weekly in some cases.

Goldfish produce lots of waste. This bio-load can quickly change levels to that of unsafe for your guppies.

Once you carry out these water changes, it is possible to remove a fair chunk of the nitrites that accumulate in the water. Although there is the chance of ammonia spikes, and these can quickly affect your guppies.

A good filter is required that is large enough to cope with keeping water clean using a good bio-filter media. Even with these large filters, it doesn’t mean you can skip testing water pH or any water changes.

One other thing with a filter capable of clearing all this waste is the flow. You may find the current is too strong for your guppies, and they become exhausted trying to swim from the current. If this happens, your goldfish may take it as a sign of an injured or a fish that is weak, and take the opportunity of a free snack.

Choose a Larger Aquarium

With all the things you need to consider for keeping guppies and goldfish in the same aquarium. One of the best ways to overcome some of these are by using a much larger tank than you require.

Doing this can overcome several obstacles, or at least help to negate some of their effects.

A larger tank has a bigger buffer against pH level swings. This means you can keep them in check easier than if you were using a smaller tank. In addition, your water heater can keep temperatures in the range for your guppies at one end of the tank.

You can also find this temperature cools a little the lower end of the acceptable range for your guppies, and is more suited to your goldfish.

Larger tanks also give a chance where you can introduce many more plants. This gives guppies many places to hide, and a larger aquascape does look good. Goldfish do like to nibble on plants, so you need to be sure you secure these into the substrate so the fish don’t uproot them inside your tank.

Plants that make a good option for use with goldfish are:

  • Java Fern
  • Duckweed
  • Water Sprite
  • Water Lettuce
  • Anubias

One good thing with these is that they require little maintenance. Even if your goldfish take a few chunks from them, they are all fast growers apart from the Anubias.

Another advantage of stocking up on plants in your tank is they can help remove nitrites in the water. This does help a little in maintaining ideal water levels for your guppies.

If you were to have a goldfish on its own, the ideal tank size is around 20 gallons. Once you introduce guppies or vice versa, you may need to up your tank size to around a 30-gallon tank to compensate for the extra fish and the guppy fry that will soon appear.

Male Guppies and Goldfish

Only having male guppies can solve the issues of your goldfish eating the fry. Although it can pose issues for your goldfish. When you have a group of male guppies, they can gang up on your goldfish, as they are known to be keen on nipping fins.

This is another area where a larger tank can help, yet they are likely to bump into each other now and again. Goldfish are a social fish, and if you have multiples in the same tanks, they will follow each other around.

One thing to note is that you should only have one kind of goldfish with one kind of goldfish. If you have pond goldfish, these ought to pair up with other pond goldfish. If you have fancy goldfish, then these par with other fancy goldfish.


It is possible for guppies and goldfish to co-habit in the same tank, although the conditions are not ideal for either kind of fish. For some aquarium enthusiasts, it is worth the effort to keep both kinds of fish in the same tank.

However, for newer tank owners, it may be too much effort to monitor their guppies continually as they keep giving birth and seeing their goldfish taking the opportunity to feed on the fry.

While it is possible for these two often-gentle fish to live together, much better parings deliver fewer problems.

If you wish to try, make sure you stick to one goldfish, because more than one will be too much for your tank and your guppies. The amount of waste can overbear the smaller fish, and overwork your filter.

If you can maintain a water temperature that is suitable for both of around 70 fahrenheit, then they can live together, nevertheless, don’t think there won’t be any issues down the line.

One final thing to ponder over is should you be keeping fish in conditions that are not ideal for them?