What Types of Fish Need a Heater in Their Tank?

Keeping fish happy and healthy is the main priority of all aquarium hobbyists. However, you don’t want to spend money on unnecessary equipment in your excitement of getting a new tank or fish breed. So, to save you money and time, here’s a quick guide to what types of fish need a heater in their tank.

Freshwater Fish

Freshwater fish come in a few types: freshwater, freshwater sub-tropical, and freshwater tropical. Depending on your fish’s breed, they may fall into any one of these categories.

Freshwater fish can vary widely. For example, the common Goldfish are often kept outside without heaters. Sub-tropical fish from areas like Florida and Arizona need a minimum of 64℉ and a max of 72℉ to live comfortably. Freshwater tropical fish, like Arowanas, need to be kept at 75℉ to 80℉ degrees, as anything colder can quickly lead to a sluggish and unhealthy fish.

Brackish Water Fish

Brackish water fish, such as Mollies, Mudskippers, and Bumblebee Gobies, start to get cold at around 77℉. While this may become specific depending on the exact regional origin of the fish, they thrive on generally warm water.

An estuary brackish water aquarium needs to be kept at around 80℉ to 82℉. A mangrove swamp aquarium needs to be held at 82℉ to 86℉, while a fast-flowing river end aquarium must be maintained between 80℉ and 84℉.

Saltwater Fish

Saltwater fish can be tropical or cold-water types. Because the ocean is generally stable and unchanging, the environment of saltwater fish needs to reflect that.

Coldwater fish, in general, can comfortably survive up to 72℉ degrees. Tropical fish can only go as low as 72℉ degrees but thrive in the 77℉ to 80℉ range. Any fish breed can be an exception to the rule, so make sure you know the exact region your fish comes from to ensure they live comfortably.

As a general rule, when it comes to what types of fish need a heater in their tank, almost every other fish breed that isn’t a coldwater fish needs a heater. Coldwater fish are often kept as pets because they don’t need a heater and are generally very sturdy breeds because of that.

However, just because a tank doesn’t need a heater doesn’t mean you shouldn’t monitor the temperature, as windows and air conditioning can quickly heat or cool a tank. For any tank, you always need a thermometer, a filter, and a sturdy hexagon fish tank stand, no matter what temperature you need to keep your tank at. So, chat with your local aquarist today to see exactly what your fish needs.