Plecos are one of the most mistreated fish in the aquarium hobby, often because of misinformation. We also see a lot of people who keep their pleco in cold water, which isn’t good at all. 

Do pleco catfish need a heater in their tank?

Plecos need a heater in their tank. They originate from the Amazon tropics, so warm water is necessary to keep them happy and healthy. Only if you live in a warm area where it’s constantly between 72°F and 80°F, a heater isn’t necessary.

Don’t be fooled by the temperature in your house, though. It might be that your house is mostly above 72°F, but a heater is still necessary to ensure the water temperature stays stable.

Why plecos need a heater

You might wonder why it is that plecos need a heater, while other fish like goldfish don’t and do fine in cold water. Well, it’s actually fairly simple.

Plecos originate from the Amazon rainforest. In their natural habitat, water temperatures are high year-round. Plecos also rely on their environment to maintain their body temperature, which is in direct correlation to their metabolism and growth rate.

Can plecos be kept in cold water?

Plecos can’t be kept in cold water, or in any temperatures below 72°F, for a long period of time. Some plecos can do well at room temperature for some time, but in order for it to thrive, a heater should always be used.

What happens with your pleco in too high temperatures

First off, your pleco will be not as active as it could be. These colder temperatures cause slower metabolism, which means your pleco won’t be able to digest its food as well. This results in your pleco conserving energy by not moving as much.

If this goes on, your pleco might even fully stop eating. And when it stops eating, it weakens even further. On top of that, the pleco will undergo a lot of stress.

These effects will ultimately cause diseases such as fin rot, ich, or parasites causing death for your pleco.

What happens with your pleco in too low temperatures

In temperatures that are too high, the opposite will happen from too low temperatures. Your pleco will start acting more active and possibly even swim to the top to take in oxygen (high temperatures mean less oxygen).

Maybe this sounds like positive behavior, but in reality, this is very unnatural and your pleco will die being “boiled” alive.

If you want to cool down your fish tank there are a few options.

It’s important to make sure your fish tank isn’t standing in direct sunlight: this will heat up the tank, cause algae growth, and even lower oxygen levels. 

The best thing you can do is take off the lid of your tank and let a fan blow over the surface. This will cause more evaporation.

The best water temperature for plecos

Because there are many pleco species that have different preferences in terms of water temperature, there isn’t one single answer for this. However, most pleco species have similar needs in terms of water temperature.

The best water temperature for plecos is between 72°F and 76°F (22-26°C). Other species like zebra plecos prefer higher temperatures 82°F between 88°F (28-31°C).


Yes, all plecos need a heater in their tank. Because they originate from the Amazon tropics, the water will need to be permanently heated to mimic their natural environment and maintain their body temperature/metabolism.

The best temperature for plecos is between 72°F and 76°F, for most pleco species. Lower temperatures cause their metabolism to fail and ultimately cause death. Higher temperatures on the other hand cause lower oxygen levels and unnatural behavior, also leading up to death.

Please take a look at our full guide on water temperature for plecos if you want to know more.