Can You Put a Heater in a Plastic Fish Tank?

Plastic Fish Tank

Most exotic fish do well in water temperatures between 74 and 82 degrees Fahrenheit. A heater can guarantee a steady temperature within that range. Without a heater, the water temperature can drop considerably in a matter of hours, causing your fish to grow lethargic and, eventually, die.

Without a lot of carelessness and blunders, it’s nearly impossible for the heater to melt the plastic. They may build fish tanks from a wide variety of plastics, but they should be able to tolerate temperatures of up to 149 degrees Fahrenheit. Water prevents the plastic from melting by dispersing the heat evenly.

This article explores the functioning of aquarium heaters in plastic fish tanks and the precautions you should exercise while implementing them.

Can Aquarium Heaters Melt Plastic?

Tropical fish of any kind, whether marine or freshwater, may be kept in warm water with a temperature over 62°F, which necessitates the use of a heater to maintain their optimal water temperature.

Despite living in a plastic fish tank, a heater is necessary to maintain the health of these tropical fish.
It is pretty unlikely that the heater will successfully melt the plastic. They construct fish tanks out of a broad range of plastics, but in any case, the polymers they choose must be able to withstand temperatures of up to 149 degrees Fahrenheit.

The water in an aquarium doesn’t need to be boiled as it would be in a conventional kitchen boiler or heater; instead, it just needs to be kept from getting too cold.

It can only melt plastic tanks if it is malfunction and is maintained extremely close to the tank wall at the same time.

Nevertheless, if you have an air stone or cooler in the tank, the plastic will never become hot since those will regulate both the amount of heat produced and the movement of oxygen in your aquarium.

It’s also quite improbable that any plastic decorations you have would melt when exposed to the heat from your heater. To be on the safe side, however, you should avoid placing any decorations or equipment made of plastic that is particularly thin or weak in close contact with the heater.

Types of Fish Tank Heaters

Here is my recommended list of heaters for plastic fish tanks:

Aqueon Preset Aquarium Fish Tank Heater is ideal for aquariums of up to 30 gallons. Fully submersible, auto shut-off when overheated, and resets when cooled.

Aqueon Pro 300 is ideal for fresh and saltwater aquariums of up to 100 gallons. Adjustable heat setting 68 to 88°F. Fully submersible, auto shut-off when overheated, and resets when cooled.

Hitop Digital Aquarium Heater adopts a digital temperature control system. It is ideal for aquariums with 75 to 180 gallons. They built it with robust and corrosion-resistant Titanium alloy, making the heating element shatterproof.

Boeespat Aquarium Heater is suitable for 40 to 60-gallon fish tanks. It has an intelligent temperature control system that automatically shuts off the power when it reaches the preset level and starts when the temperature is lower.

Hygger Aquarium Heater is suitable for marine and freshwater fish tanks with 80 to 190 gallons. It has an external digital display controller and a double tube heating element. It can automatically shut off on reaching preset levels and also has running-dry shut-off protection to stop working when exposed to air.

Can You Use a Heater in a Plastic Fish Tank?

Yes, it is perfectly safe to use a heater in a plastic fish tank. The integrated thermostat of the aquarium heaters ensures that the water always remains within a few degrees of the desired temperature. When the preset temperature is reached, the power will automatically switch off as a safety precaution.

But always make sure that you have a thorough reading of the instruction booklet that came with your fish tank heater before you attempt to install it.

It is recommended that the heater not be plugged in until after you have placed it in the aquarium and given sufficient time to acclimatize to the temperature of the water.

The same thing happens for taking off the heater from the aquarium. Wait until it has cooled down before removing it.

If you notice anything unusual, especially if it gets to the point where your plastic tank is more than warm, you should replace the fish tank heater as soon as possible since it is likely faulty or malfunctioning in some way.

The reality is that such an incidence is extremely uncommon since, even if the gadget malfunctions, there is still water in the fish tank to keep it cool so that it does not become too hot and melt the plastic tank.

By distributing the heat in a more uniform manner, water in the tank helps to prevent the plastic from melting.

Should You Turn Off the Heater at Night?

If you reside in a colder climate region, then you may leave the heater on at night. The easiest technique to manage the temperature of the fish tank water is to switch it on and off automatically. If it remains on and causes the water to get excessively heated, it must be replaced.

There are several advanced heating systems available, each having automated on/off switching and a thermometer for monitoring the temperature.

Ideal Position for Aquarium Heater

You should install submersible aquarium heaters at the tank’s bottom. They can be positioned vertically if that is more convenient for you.

You may ensure that there is a uniform dispersion of heat by putting your heater so that it is close to either the inlet of a filter or a circulation pump.


Invest in a good quality fish tank heater for your plastic aquarium tank or container, and you won’t have any problems with keeping the water at the appropriate temperature. However, while using a fish tank heater, you should always observe the safety procedures that are described in the instructions provided by the manufacturer.

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