There are so many interesting fish out there, but not all of them can live together. I wondered whether my guppies and goldfish could live together in the same aquarium. Here is what I found out.
It is best to not keep guppies and goldfish in the same aquarium. They prefer different temperatures. Goldfish will grow large enough to eat guppies and guppies are known fin nippers that might damage the beautiful fins of your goldfish. Overall, it is a bad idea that will lead to dead guppies.
If you are someone who has been keeping goldfish and guppies together you might think that this article is irrelevant or even false. But think again and notice what is really happening in the aquarium.
Temperature difference is too big
Temperature is the first reason why I would not keep guppies and goldfish in the same tank. You see, guppies are tropical fish and require tropical temperatures. Goldfish on the other hand actually are better suited as pond fish. They are cold water fish who prefer cooler water.
A guppy thrives at a water temperature around 77 °F (25 °C). These are tropical temperatures, and chances are that you already have a tropical aquarium set up that has the same water temperatures.
Goldfish can stand these warmer temperatures for a short while, for example when kept in a pond in summer, but they are not comfortable being kept in tropical temperatures all the time.
Goldfish would rather prefer water temperatures around 65 °F (18 °C).
Keeping guppies in cold water makes them way more susceptible for illness and they might even refuse to eat. Keeping goldfish in tropical temperatures gives them a lot of stress and seriously reduces their lifespan.
Goldfish grow way too big
While there are different subspecies of goldfish, they will all grow way bigger than a guppy. Smaller fancy goldfish varieties will grow to 6 inches (15 cm) while other more common goldfish grow to up to a foot (30 cm) long.
When you buy goldfish and guppies in the store, they might be at a size that they could potentially stay in one aquarium in peace. But as soon as the goldfish seriously outgrows the guppies, they will see their tankmates as tasty snacks.
While goldfish are generally peaceful fish, they will definitely eat the guppy fry and eventually the adult guppies. This is just how nature works, bigger fish eat smaller fish.
Guppies are fin nippers
Guppies and goldfish have a completely different temperament. If you choose to only keep male guppies because they are more colorful and do not reproduce, you know that they like to have a go at each other. There is a lot of “action” within a group of guppies.
Goldfish on the other hand are known to be peaceful fish. When you put the two together, the guppies will definitely harass the goldfish. Providing enough space might solve this, but they will definitely find each other every now and than.
The result of the mix will be a lot of torn fins, especially when you have a variety of goldfish with long fins.
Feeding will become a problem
Despite having different dietary needs, goldfish are extremely greedy eaters. They will devour everything your drop in the tank, pushing aside other fish and claiming the food as their own.
Now image being a small guppy trying to get to the food.
Yes, guppies are fast, but with goldfish in the tank it becomes difficult to feed all the guppies in the aquarium. There is no way to know for sure if everyone has had enough food.
Sickness and diseases
When fish live in a water temperature that is far from their optimal temperature, they are way more susceptible to become ill. So guppies in colder water can become sick quicker, and the same goes for goldfish in warmer water.
Also, because guppies and goldfish are so different from each other, you will also be dealing with different kind of diseases which might need their own kind of treatment.
Goldfish like being with goldfish
Goldfish are rather social fish. If you have kept multiple goldfish in an aquarium before you will know that they like to follow each other around in the tank.
Also, goldfish can only be with the same type of goldfish. Common or “pond” goldfish can only go with other common goldfish while fancy goldfish can only be with other fancy goldfish.
Will goldfish eat guppies?
Because of the size difference it is very likely that goldfish will eat guppies. Goldfish tend to eat anything that fits in their mouth.
Guppies, especially fry or male guppies, do not grow very large.
Because of these fact, it is only obvious that goldfish will eat guppies. If not immediately, they will catch the guppies within a few days. So even if you think that it might just work out, it is only a matter of time.
Can guppies live in cold water with goldfish?
There are many people who want to keep guppies in a pond. In fact, a guppy pond is a common habit among hobbyists that live in warmer climates. However, if you live in a colder climate this is not possible.
Goldfish are cold water fish and can not get used to the warmer temperatures. Therefore, they belong in a pond or a large unheated aquarium. If you want to add guppies to the same pond, you run into the same temperature problem that I described earlier.
In short, no: guppies can not live in cold water with goldfish.
Could you make it work?
At the end of the day it is of course up to you what you put in your aquarium. There are people who compromise in the temperature and have kept guppies and goldfish together for a while. But what do you think? Is it fair to the fish to put them together?
If you would go for it, make sure you have the option to quarantine the fish. Have a small tank ready to put the fish in before you add them together, so you can observe them for a couple of weeks and make sure they are perfectly healthy.
You might also need the smaller tank in between to cure different diseases or to separate the fish when needed.
Remember that the fish in your aquarium rely on you to provide them with all their needs. And don’t you agree that it is our duty to replicate their natural habitat as best as possible?
If you still want to keep guppies and goldfish, it might be best to provide them with their own aquariums.
Can guppies live in an outside pond? Depending on your climate, guppies can live in a pond. If you live somewhere warm like Florida they will do well, however if you live in more moderate temperatures like the UK, Germany etc, they will die.
Can guppies be kept with shrimp? Yes, this is possible. If you have shrimp that breed in freshwater, you will most likely not see your shrimp colony grow. This is because the guppies will eat most of the baby shrimp.
Can guppies and endlers interbreed? Yes, this is possible. You will get healthy fry.