Platy Fish and Goldfish – Can You Keep Them in Same Aquarium?

Since both platy fish and goldfish are beginner-friendly fish that have easy-to-fulfill keeping requirements, you may think they’re compatible and you could perhaps keep them in the same aquarium.

Unfortunately, goldfish aren’t a good match for platy fish. While you could technically place them in the same freshwater tank, they won’t get along all that well, nor will they adapt to each other’s water requirements.


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In this article I discuss the reasons why platy fish and goldfish should not be kept in the same aquarium and how to choose compatible tank mates for your fish.

Here’s why platies and goldfish are not compatible:

Why You Shouldn’t Keep Platies and Goldfish in the Same Aquarium

Platies and goldfish aren’t a good match because of differences in keeping requirements that are difficult to adjust so that both fish are in their comfort zone.

To help you better understand why goldfish shouldn’t be kept with platy fish, I’ll explain the differences that make them incompatible.

Of all their incompatibilities, water temperature and tank size requirements are the most important aspects.

1.  Water Temperature

Even though both are freshwater fish, their water requirements are different. Platies are tropical fish that enjoy warmer waters in the range of 72°F- 78°F (or even a little above this range), goldfish on the other hand, are tempered water fish.

Goldfish can survive in water between 60° and 74° F, and they feel best in colder waters. While platies require a heater in their aquarium, goldfish don’t do well in aquariums with heaters, and they’re in their element without a water heater in the aquarium.

Forcing one or the other to adapt to water conditions that aren’t ideal will eventually lead to health problems that once appear will be difficult to overcome.

In terms of other water parameters, platies like water that has a pH at around 7.0-8.3 and water hardness between 4 – 12 dGH.

For goldfish, water pH isn’t critical, still their preferred range is between 7.0-8.4 and water hardness should be up to 12 dGH. So, in terms of these parameters, their requirements are pretty much lined up.

2.  Tank Size

Platies don’t grow as big as goldfish. Platies reach sizes of 2.5 inches at most, while goldfish can grow up to 12 inches in size.

This means that while platies may do fine in the spacious, 50 gallons or more aquariums dedicated to goldfish, goldfish won’t be happy with the 15-20-gallon aquariums that platies are mostly kept in.

It’s a misconception that you can keep goldfish in small bowls or aquariums. Goldfish have a long lifespan and are fish that become large once they reach adulthood.

They also produce a lot of waste, which will quickly alter the water chemistry in a small aquarium and cause health problems or even death if water changes are not performed regularly.

3.  Feeding

Goldfish should not be kept with aggressive or boisterous fish. And while platies are in no way considered aggressive fish, they may be a little too lively for goldfish.

This liveliness may make itself even more noticed at feeding time, when platies will quickly devour food at feeding time leaving goldfish wanting for more food.

4.  Behavioral Issues

Although I haven’t seen it myself, some aquarists report that their platies have chased goldfish around in their tank.

Although platies are peaceful and usually keep to themselves, it may happen that they will take issue with some fish, although it’s unlikely that they’ll attack any fish.

It’s more likely, however, that because of the huge difference in size, goldfish may inadvertently eat platy juveniles. Still, platy juveniles can be eaten even by their own kind if they’re kept together with adults.

5.  Maintenance

Goldfish produce a lot of waste in their aquarium, easily causing ammonia spikes, especially in smaller aquariums.

A strong filter is not optional when keeping goldfish as well as frequent water changes. Although a filter is recommended for platies, depending on how stocked your aquarium is and whether it’s planted or not, you may get away with keeping platies without a filter.

Choosing Tank Mates for Your Fish

When choosing tank mates, compatibility should be researched and examined with respect to the following aspects:

  • Water conditions including tank size, water temperature, pH and hardness;
  • Compatibility in behavior (fin-nippers should not be kept with fish that have long fins, aggressive fish should not be kept with peaceful fish, very small fish should not be kept with large fish that might mistake them for food, etc.);
  • Dietary requirements (it’s ideal if fish feed on the same types of food);
  • Disease susceptibility and treatment.

As you can see, there are various factors at play when deciding if you should keep certain fish together or not. Doing your research will save you from having to deal with the problems that arise like injuries, nutritional issues, health problems, etc.

Fish Compatible with Goldfish

If you’re looking for fish that are an excellent match for goldfish, I encourage you to choose one or more of the following fish species: bristlenose plecos, rubbernose plecos, rosy barbs, zebra danios, white cloud mountain minnows, and tetras.

Choosing compatible tank mates for your goldfish will ensure a healthy, stress-free environment in which all the inhabitants of the aquarium can peacefully coexist.

Fish Compatible with Platies

Platies are compatible with many tropical freshwater fish including guppies, swordtails, endlers, zebra danios, neon tetras, mollies, minnows, corydoras, plecos, gouramis, rosy tetras, etc.

Platies are active and peaceful fish that should be kept with fish that have similar temperaments and water requirements.


Even though platy fish and goldfish don’t enjoy the same water conditions, and should not be kept together, there are plenty of other fish you can select for your platies or goldfish.

It’s important to research the requirements of each fish and prevent any injuries in the aquarium by choosing fish that have the same temperament.

I hope you now understand why you shouldn’t add goldfish to a platy aquarium, or vice versa, and you’ll pick compatible tank mates instead.

Questions and Answers

Caroline Findlay December 31, 2019 Reply

I had 2 gold fish in a 40 litre tank. The pet store said it was fine to add 4 platys .
After a few weeks one platy disappeared! One looked sick, staying at bottom of the tank.
I removed the 3 platys into their own smaller tank. They’re much better now but not sure if the third one will recover. It’s still alive so far.
Don’t keep gold fish and platys together! The goldfish must have ate the other platy!

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