How to Keep a Fish Tank Warm in a Cold House

Like reptiles, fish cannot regulate their own body temperature. The water temperature determines the temperature of the fish. For tropical fish commonly kept as pets, a cold house can be deadly as the water temperature becomes the same cold temperature as the air in the house. In the summer, you may not need to worry about your tank̵7;s temperature, but in the winter, you will need a heat source for your fish to keep them healthy.

Things You'll Need

  • Aquarium heater
  • Aquarium thermometer
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Instructions

    • 1

      Install an aquarium heater in your fish tank. There are several options for aquarium heaters, all of which you can purchase at any pet retailer that sells fish supplies. Choose a heater designed for your tank̵7;s size and within your budget. Follow the package instructions for installing the specific aquarium heater that you choose.

    • 2

      Install a thermometer on or in your tank if the heater does not come with one. You will need to monitor the temperature of the tank throughout the day to ensure you do not overheat the fish. Options include digital thermometers with sensors that you insert into the water, or for a less expensive option you can choose a thermometer the sticks to the outside of your tank and changes color with temperature changes.

    • 3

      Determine the optimal temperate range for the types of fish in your tank. This will be the temperature range you need to keep the tank water in. Books such as ̶0;500 Freshwater Aquarium Fish̶1; and ̶0;Freshwater Aquariums for Dummies̶1; list the temperature needs for various fish species.

    • 4

      Set the aquarium heater to the appropriate setting to maintain the water temperature as per the heater package̵7;s instructions.

    • 5

      Check the temperature of the water at least twice a day. You may find that you need to adjust the heater setting in the evenings and during the middle of winter if your house gets even colder during those times.