Aquarium fauna usually lives in warm water, a constant ambient temperature is a prerequisite for the life, especially for tropical species. Fish are cold-blooded creatures which body temperature directly depends on the ambient temperature, therefore, experienced aquarists use a water heater for an aquarium, which not only heats the water, but also performs other important functions: maintains an optimal temperature, normalizes the microclimate, and positively affects the life of aquatic inhabitants. The average water temperature for fresh and tropical reservoirs is 23-30 degrees. A slight increase is necessary if the room is quite cool or tropical fish species live in the aquarium. This article presents the TOP 5 aquarium heaters.

What are the best aquarium heaters to buy in 2021?

1. Glass submersible heaters

MODUODUO Fish Tank Heater (under $10)

MODUODUO fish tank submersible heater

The body consists of a shockproof, heat-resistant glass tube, which is closed with a sealed plastic lid and is completely submerged in water. It contains a thermostat, a temperature controller for adjusting the temperature. The heater turns on and off automatically while maintaining the set water temperature. 2 suction cups allow you to fix the device on any aquarium wall.

2. External heaters

JEBO 100w - 1200w External Heating Bar (under $50)

JEBO external aquarium heater

The heater is connected to the return filter hose. This way the heat is better distributed. The water that passes through both devices is purified and heated at the same time. The plastic case is made of a reliable material and protects the parts of the device. The heater is installed next to the aquarium – the device works outside, so there is a lot of space in the aquarium. The disadvantages of this type include high energy consumption. You can choose the suitable option between 100w and 1200w.

3. Mini heaters for aquariums

Aqua Syncro Ultra-thin Flexible Mini Aquarium Heater (under $15)

Aqua Syncro ultra-thin flexible mini aquarium heater

Such devices have a flat shape, so they can be placed anywhere (the design is flexible), even under the ground. The are suitable for both fresh and sea water. The main purpose of such devices is to heat small aquariums. The only drawback is the lack of thermostats, which requires measuring and adjusting the temperature. Available options: 7.5W / 15W

4. Titanium heaters

Titanium Aquarium Thermostat 500W (under $50)

Titanium aquarium heater

It is a high-precision device with an information display showing the water temperature. Besides, the heater allows you to control the temperature without dipping your hands in water. The combination of modern technologies makes it possible to use the device for both fresh and sea water. The heater is also great for aquariums with large turtles and fish. It is suitable for large aquariums. Can be stuck to the inner aquarium walls through suction cups. Temperature indicating scale can be adjusted between 20-34°C (68-93°F).  The thermostat is equipped with a LED on / off indicator.


5. Oval heaters for turtles

Sunsun Heater for a Turtle Tank 50W-150W (under $20)

Sunsun digital heater for a turtle tank

This heater is interesting because of its unique oval shape, and it is perfect to provide a constant automatic temperature. The temperature is set at the touch of a button and there is a bright LED display that allows you to see the temperature immediately. The only caveat of this heater is that small fish can get stuck in it because of its design. The heater is very popular with turtle owners.


How to choose an aquarium heater?

The choice of a heater should be made with all responsibility, since the health of small pets depends on it. It is necessary to pay attention to the following parameters:

  • power. It must correspond to the volume of the tank. Indicators – 0.8/1 W per liter;
  • thermostat – this is a device that maintains the required temperature, when the desired value is reached, the device will turn off automatically, if the temperature drops again, the device will start heating water;
  • installation and fastening method. The design doesn’t have to be complicated;
  • presence of an emergency shutdown system. It will work as soon as the water level in the tank falls below the “Minimum” mark;
  • temperature adjustment type: some models have automatic temperature adjustment, while others require manual adjustment;
  • if you have a seawater tank, choose a heating device that can be used in salt water.