Heaters & Accessories
Maintaining the right water temperature for your fish is vital, as fish can’t regulate their body temperatures like we do. Make it easy and straightforward with these great heaters, thermo-sensors and thermometers, specially designed for fishkeeping.
Fish require very strict temperature regulation to be happy and healthy. Making sure their water doesn’t get too cold is key, especially if they’re tropical fish, so you’ll need to buy a water heater that’s the right size for your tank.
Types of Aquarium Heaters
Hang-on-tank: Hang-on heaters mount onto the rear of the tank (typically) with suction cups and/or a hook or other fastening device over the edge of the tank. They are only partially submerged and tend to be less efficient than other types of heaters, but they can provide adequate heating in smaller tanks. When used in large tanks, it’s best to have more than one hang-on heater at opposite sides of the aquarium.
Submersible: Submersible heaters are completely submerged in the tank water and mount to the back of the tank either horizontally or vertically. Often, they are mounted horizontally near the substrate. Submersibles generally provide more consistent and efficient heating than hang-on heaters, especially with larger tanks.
Heating cable: A heating cable is placed under the gravel or substrate and is connected to a control unit. It can be useful for freshwater planted aquariums to eliminate dead spots. However, because you have to dig up the substrate if the cable needs to be repaired or replaced, this type of heater isn’t the best option for saltwater reef systems.
100w Submersible Heater
Hidom
£9.99
50W Submersible Heater
XiLONG
£9.49
25W Submersible Heater
Uniclife
£10.29
50W Submersible Heater
Uniclife
£10.49
300W Submersible Heater
XiLONG
£13.99
100W Submersible Heater
Interpet
£3.60
300W Submersible Heater
U-picks
£19.99
10w Nano Stat Heater
Interpet
£10.99
50W Submersible Heater
Hygger
£19.99
Finding the Right Aquarium Heater Size
Sizing a tank heater (or heaters) is based on the water volume of the tank, the average temperature in the room where the tank is located, and the desired water temperature for the tank.
For the heater wattage, the basic rule of thumb is to use between 2.5 and 5 watts per gallon of actual water volume in the aquarium. However, often more wattage is required, depending on how much you want to raise the temperature. If you’re using more than one heater, the total heating capacity of all the units together should add up to the required wattage.
To adjust for the room temperature, subtract the average temperature of the room from the target temperature for the aquarium water. The result is the amount of heating required, measured in degrees.
Using the aquarium heater size chart below, find the size of your aquarium in the left-hand column, then move to the column that shows the number of degrees the aquarium needs to be heated. If the heating requirement is between levels, move up to the next larger size.
Example:
- Average room temperature: 68 degrees F
- Target water temperature: 77 degrees F
- Heating required: 9 degrees F (77 – 68 = 9)
- Tank size: 20 gallon
- Heater size needed: 50 watts
| Tank Size | Heat 5 Degrees C 9 Degrees F | Heat 10 Degrees C 18 Degrees F | Heat 15 Degrees C 27 Degrees F |
| 5 Gallon/20 Liter | 25 watt | 50 watt | 75 watt |
| 10 Gallon/40 Liter | 50 watt | 75 watt | 75 watt |
| 20 Gallon/75 Liter | 50 watt | 75 watt | 150 watt |
| 25 Gallon/100 Liter | 75 watt | 100 watt | 200 watt |
| 40 Gallon/150 Liter | 100 watt | 150 watt | 300 watt |
| 50 Gallon/200 Liter | 150 watt | 200 watt | two 200 watt |
| 65 Gallon/250 Liter | 200 watt | 250 watt | two 250 watt |
| 75 Gallon/300 Liter | 250 watt | 300 watt | two 300 watt |
