Do Platy Fish Need A Heater? Water Temperature And More

The Platy fish is one of the most popular freshwater aquarium fish, and it’s not hard to see why! These little guys are so adorable with their big eyes. They’re active swimmers who love to play in the water. But there are some important things you need to know about them before you get your own! Like how do Platy fish feel about heaters? Do Platy Fish need a heater in their tank?

Yes, Platy Fish needs a heater. Platies are tropical fish and prefer warm water around 25°C (77°F). If tank water temperature becomes extreme, platys will die from either too cold or burning hot.

And what happens if tank water becomes too cold or too hot? There are even more questions you need to find answers to. Find out more in this blog post!

Do Platy Fish Need A Heater?

Yes, Platy fish need a heater, but not for the reason you think. Platy Fish are tropical fish and are cold-blooded animals. So, they depend on their environment to maintain an appropriate level of body temperature.

Platy Fish are not particularly picky, but if you have a particular type of fish in mind, it’s important to research what temperature they need for their habitat.

What Is The Ideal Water Temperature For Platy Fish?

The ideal temperature for platys would be between 78-82 degrees Fahrenheit (25-28°Celsius). In warmer water, the fish will require less heat than those living in cooler waters. However, too Cold, and they will be sluggish, too hot, and they can get stressed or develop a bacterial infection.

What Will Happen If The Temperature Of Tank Water Becomes Extreme?

If the water temperature is too cold, your Platy Fish will not be able to survive. If it’s too hot, they won’t thrive and can suffer from burns on their body. The ideal tank temperature for a Platy fish varies depending on what species you have in your aquarium. Some common types of platies are Common Gold, Black, and Red.

Too Cold:

When the water in your aquarium is below 18-19°C, one cannot maintain homeostasis. Fish will start to shiver, and it’s a sign of hypothermia in the fish. This can lead to death when prolonged over time.

If the tank water becomes too cold (less than 68° Fahrenheit), then your fish may not feel well due to their slowed metabolism, which could cause them to stop swimming around and eating.

Too Hot:

When the water in your aquarium is above 27-28°C, it won’t maintain homeostasis with decreased oxygen levels that could result in suffocation due to lack of oxygen.

Too Hot (more than 82° Fahrenheit) and the fish could develop a bacterial infection, or they will stop eating.

It’s a good idea to invest in an aquarium thermometer so you can make sure the temperature is not fluctuating too much or going below what your Platy Fish need for their habitat. The water should be between 76°F-82°F (24°C-28°C)

What Happens If The Temperature Changes Suddenly?

If the water temperature changes suddenly and drastically, your Platy Fish will experience shock or even respiratory problems due to sudden change and lack of oxygen.

To prevent these problems, it is necessary to buy a spare heater for your Platy Fish or use an external thermostat and maintain the water temperature at all times. (This will also help you in case of power failure.)

How To Choose The Right Heater For Your Platy Fish?

Heaters are rated in watts. A watt is a unit of power, so the more powerful your heater is, the quicker it will heat water and maintain that temperature when necessary. Larger fish tanks require larger amounts of energy to keep warm – meaning you need a higher wattage heater. You can get away with something less powerful for a smaller tank that will work at slower rates.

For example, A 50-watt heater is usually enough for an aquarium up to 55 gallons in size, whereas a 250-watt heater would be more appropriate for 200 gallons or larger tanks.

Heater Watt Size Guide

50 watts = up to 55-gallon fish tank

75 watts = up to 90-gallon fish tank

150 watts = up to 120 gallons fish tank

200-250 watts= over 200 gallons (up to 300) aquariums or larger tanks. Proceed with caution for smaller tanks as the temperature can get too high if you use a heater that is too powerful

Types Of Heaters


These are usually the most popular heaters because you can hide them out of sight by placing them inside the tank. The downside to this type is the risk of electrical shock if you have an aquarium with low water levels.

The heaters are made in a variety of sizes, as well: from small clip-on models for a single tank to more powerful and larger ones that can cover up to 100 gallons at once. The size you select will depend on the size of your tank or fishbowl.

For example, if you use an aquarium heater with a capacity of 50 gallons, it’s safer to use a clip-on model for small tanks. I recommend you to use AQQA Submersible Aquarium Heater for the Platy Fish tank.

Ultraviolet Heating Lamp:

If you’re looking for something that can provide continuous heat without having the expense and hassle of an aquarium heater, then this is your best option. Ultraviolet lamps will help keep the water temperature at the desired level on top of a tank, thus eliminating the need for a heater and filters.

Where Should You Place The Heater?

A heater is a vital piece of equipment for any fish tank owner. If you have Platy fish, they need to be kept in water with the right temperature and no sudden changes.

You can purchase an aquarium or submersible heater, but these are not always recommended if your setup does not allow you to control the placement of the heater.

You should place your heater at one end of your aquarium or fishbowl so that it will be able to provide heat evenly throughout the water’s surface area. For small tanks like bowls or cups, you can put them right in the water.

If not, the heater will likely be too close to your fish and could potentially fry them or cause burns if it malfunctions in any way. And this is also a problem with external heaters hooked up outside of the tank as they can get knocked over easily by pets that are curious about what’s going on inside the aquarium when you’re not looking.

The good idea is to get a heater guard that will protect the aquarium walls and your fish from any potential accidents concerning heating devices, whether they are external or internal.

If you have a design for an outside-the-tank heater, then this isn’t an issue as there’s no way it can be knocked or bumped over by an animal.

Is Buying A Thermometer Necessary?

Yes, kind of. While a thermometer is not necessary, it can be helpful. If you’re unsure of what temperatures are good for Platy fish, then yes, buying a thermometer is advisable so that you know where your tank is at all times.

If your tank temperature gets too cold, then the platys will stop eating, and they’ll prefer to stay in their hiding spot.

Platy fish tanks can get very warm if you don’t have a heater or thermometer to check it constantly, so make sure that you keep an eye on how hot it is, or you might risk burning your fish.

A thermometer will help you keep track of your fish’s temperature is. And it’ll also tell you if a heater needs to be adjusted or replaced with one that has more power for the size tank.

They can range from basic models, which are nothing. But a glass tube filled with mercury goes from solid to liquid at a specific temperature to digital models with built-in thermometers and alarms.

Do Baby Platy Fish Need Heater Too?

Yes! Many people think because baby platys are small, they don’t need as much heat in their water, but this is not true. The ideal water temperature for baby Platy Fish is the same as that of adults.

In the early stages of life, your baby platies must stay at 68°F and should never exceed 80° degrees Fahrenheit. Of course, you’ll need an external thermostat or monitor to maintain this temperature.

Should You Invest in A Spare Heater For Your Platy Fish?

Yes, this is a wise investment and one that can save you from experiencing any of these problems in the future: shock, respiratory problems, temperature changes suddenly. It’s even more important if you have delicate fish like baby platys that need higher temperatures.

If you have an aquarium or fishbowl, it’s never a bad idea to invest in another heater just in case one goes out, and your other one can’t get there fast enough.

A spare heater will also come in handy when you have two tanks that need to be heated simultaneously. It’s not always possible or practical for one of your heaters to do both jobs, so a backup is essential.

This way, if one goes out and needs replacing, there’ll be no interruption in water temperature, making it uncomfortable for your fish.

What To Do In Case Of Power Failure?

If you have no power or backup power source, the water will eventually cool, which could be bad for your fish.

You’ll want to keep an eye on this situation until power is restored so that if the temperature falls below 68°, you can boost up the heat with a heating pad or heater.

You can buy backup battery packs so that you will have enough time to take care of your fish during an outage and not leave in a rush when the power goes out unexpectedly, or invest in a generator if one is available near you. If it’s too cold outside for you to plug in an extension cord, a generator will be your best option if it’s available.

If the power is out for more than two hours, experts recommend that you immediately move all of your fish into something with heat like a spare tank or bathtub and ensure that their water temperature stays at 68° degrees Fahrenheit.


Do Live Plants In A Platy Tank Need A Heater?

Live plants in a platy tank will need to be heated if the water temperature is below 65 degrees Fahrenheit.

Platies can handle warmer temperatures than 55 degrees Fahrenheit. But live plants cannot, so it’s best to keep them at about 70-75 degrees Fahrenheit for their health and well-being.

Can You Keep Platy Fish In Ponds?

Yes, you can keep platies in ponds as long as the water temperature stays at about 68 degrees Fahrenheit. These fish are quite wonderful even for the fishkeepers who want to keep a bigger pond.

How Do You Tell If A Platy Fish Is Dead?

If your fish is floating motionlessly on top of the tank, it’s likely dead, and you’ll want to remove it from the tank ASAP.

If their eyes are cloudy, they may not be dead yet. So, you’ll need to wait a few hours and observe the fish for any signs of movement.


In conclusion, it is important to have a heater in your platy tank. It doesn’t really matter what wattage size you buy, as long as it can maintain the temperature of the water at an appropriate level for the fish inside.

If you want to keep your Platy fish healthy, it’s important to pay attention to their water temperature and make sure that they stay in the correct range.

If you have any questions, please feel free to contact us and we will gladly answer them for you.

Good Luck!!!

Happy Fishkeeping!!!