Do Plecos Need A Heated Tank? {What is the Optimal Temperature?

Are you thinking about putting your plecostomus in a tank without a heater? Are you wondering do plecos need a heated tank?

What is the coldest temperature a plecostomus can handle?

Below I will cover everything you need to know.

Do Plecos Need A Heated Tank?

Yes a pleco thrives in much warmer temperatures ranging from 74-80° F. A heater is recommended for tropical fish like plecos.

If a plecos is kept in cooler water they will not thrive and are very likely to become ill and develop other conditions which I will cover below.

Can Plecos Survive In Cold Water?

Over 150 types of plecostomus have been discovered in the wild. It’s hard to tell which ones are the most hardiest to withstand cold water. Although they may survive, will they thrive?

Are you looking to keep your plecos in an outdoor pond? Be aware that plecos are tropical fish from fast moving cuurents in South America. You will have to keep your temperatures similar to tropical conditions ranging from 65-85°F, but this range may prove to be too wide.

  • Bristlenose Pleco
  • Bulldog Pleco

Both types of plecos listed above are hardy enough to withstand cooler temperatures. This doesn’t mean they will survive winter months or cold waters for long periods of time. It’s best to keep all your plecostomus in warmer ranges at about 74-80°F.

What Happens When A Plecostomus Is In Colder Water?

Your plecostomus will appreciate warmer water that doesn’t fluctuate. Water changes with cooler water added it to the tank tends to cause stress for a limited time. You may notice a cold plecostomus displaying the following features:

  • discoloration
  • erratic swimming
  • swimming in circles
  • excessive hiding
  • no appetite
  • glass surfing
  • jumping

The pale skin color will restore itself when the water warms up. Your plecostomus should be relaxed, motionless at times, hiding and resting through many parts of the day.

The activity levels increase at night when it’s time to explore. The cooler water produces stress that may lead to the desire to swim up and down and possibly attempt to jump out.

If your plecostomus gives up eating, then something is wrong. Warm up the temperature to prevent parasites from thriving and help replicate warmer tropical waters.

Should I Get A Heater For My Plecostomus?

Heaters continue to get cheaper, more energy efficient, smaller and less of an eyesore in your tank. They provide an essential service to your tropical marine life. Plecos like temperatures to remain in the mid to high seventies. 74-80°F is where we like to keep it.

Attach a thermometer if one is not included with the heater. If you can keep your room and water temperature between 70-80°F all year round, then you may not need a heater.

YouTube video

Which Heater Should I Choose For Plecos?

Heaters vary in models and sizes. There are many used or cheaper models. You may need two heaters at opposite ends of a larger tank for your plecos. We like the following heaters, but we aren’t paid to endorse any specific model.

  • Fluval E Series
  • Eheim Jager
  • Aquarium Masters

Make sure to follow the guidelines for heaters. The general rule of thumb is 5 watts of power per gallon of water.

  • 50-60 Gallons: 200 Watts
  • 75-100 Gallons :250-300 Watts

You shouldn’t go any smaller with tank size or heater wattage when stocking even a single average sized plecostomus over 10 inches in length. Make sure there is a plastic guard to keep your suckermouth plecos from attaching themselves to it.

Can Bristlenose Plecos Live Without A Heater?

A Bristlenose Pleco has been found in waters as cold at 50°F. This is far too cold for most types and even for a Bristlenose. The ability to survive under such frigid conditions will surely exhaust the organs and lead to an early death.

A Bristlenose Pleco is the most popular type of plecostomus that can live in your room temperature tank without a heater. They get along in a community tank with peaceful, mid or top level tankmates.

Please check for the compatible water parameters when choosing tankmates and ensure that they can also withstand a tank without a heater. Ensure that there are no fluctuations overnight.


Most plecos can tolerate a large range in water temperature. 60-85°F ranges are common in the wild, but sensitivity levels rise in captivity. When creating your own ecosystem for plecos to thrive more many years to come, please try to keep optimal temperatures at 74-80°F.

If you can do this without a heater, use a thermometer only to make sure you are correct. If not, look to buy a heater or two with 5 watts of power for every 1 gallon of water in your tank.

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.