Why Does My Plecostomus Hide? {7 Tips To Help Plecos Become More Active}

Is your plectostomus hiding from you and the world? Is your plectostomus sick or just resting? In this article, we’ll uncover the topic of why a plectostomus hides so often.

Why Does My Plecostomus Hide? Your plecostomus is primarily nocturnal. During the day, the hiding spaces provide shade or dimly lit comfort for plecos to rest as it replicates their natural habitat.

Is A Plectostomus Nocturnal?

Many plecostomus or suckerfish are primarily nocturnal. That is to say, they can still be found scavenging or swimming during the day. There are behavioral variations among the types of plecostomus out there, but most prefer to remain hidden while they rest during many parts of the day.

At night, their natural tendency is to come out and look for algae. Through time, you can introduce more hiding spaces for rest and different types of foods to keep your plecostomus happy and active at their own schedule.

Why Is My Plecostomus Lying Motionless?

Sometimes we worry that our plecostomus is trying to tell us something in its motionless state. Is the water quality off or an illness present? More often than not, your pleco is simply resting during the day. Other possible reasons for lethargic behavior for extended periods of time may involve the following:

  • lack of oxygen 
  • too hot
  • too cold
  • ammonia spikes
  • aggression from tankmates
  • lack of food
  • too much light
  • not enough hiding spaces

Decorate, aerate and oxygenate your tank with densely planted areas. Add rocks, caves and a powerhead to make currents for sending their waste off towards the intake of a powerful filter. Your lazy, messy, but happy plecos will thank you for your efforts to keep them comfortable.

Is My Pleco Hiding Out Of Stress?

A stressed plecostomus will not only hide of out of stress. Being primarily nocturnal, it prefers darker, secluded areas to rest during the day. Look for the following indicators of stress that is worse that simply hiding:

  • swimming in a circular motion
  • glass surfing up and down the tank
  • not eating
  • discoloration or paleness
  • panting or irregular breathing

Hiding is more about protection from perceived threat or danger. Even if there is no need to feel fear, your plecostomus doesn’t know that. Hiding is an effective defense mechanism.

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How Can I Make My Plecostomus More Active?

An active plecostomus is probably searching, scouring, rummaging and scavenging at night when you’re not around. The lights are off and most tankmates are resting. This is when your pleco wants to keep its body close to the substrate or other objects. It feels and looks for algae or other sources of food.

If you want more activity out of your plecostomus, consider these strategies:

  1. visible resting areas such as rock or driftwood
  2. offer live insects
  3. get a larger tank
  4. rearrange the decorations
  5. introduce a variety of suitable tankmates
  6. vary their diet
  7. maintain optimal water parameters

Rocks and Driftwood

The don’t need to be hidden out of view. The shapes and sizes of rocks or driftwood can be such that your pleco may enjoy resting there, but remain within plain view.

Insects and Invertebrates

Your plecostomus is an omnivore that naturally focuses on algae. A captive pleco lives on for years and adapts to eating a variety of protein and nutrient rich food that you offer.

Live insects and invertebrates may catch the eye of your pleco and entice it to come out for a chance at a meal that is moving around the substrate.

Larger Tank

How big is your tank? Sometimes this is all it takes for your pleco to come out of constant hiding. Some say 50 gallons will suffice.

You may notice a higher amount of activity in a 75 or 100 gallon tank with a pleco that grows 12-15 inches in length. Offer more room and they might enjoy roaming more frequently.

Rearrange Everything

Try a different setup with your caves, rocks and decorations. Try to keep their favorite spots near the intake of the filter to suck in the excess waste they create or open the spaces up to see your pleco more often.

Adjusting may cause stress. Rearrange things one piece or plant at a time. Doing it all once may cause your pleco to hide away even more.


It goes without saying that your plecostomus would enjoy peaceful tankmates that don’t bully for food or territory. Here’s a list of suitable tankmates for most plecos:

  • Corydoras
  • Molly Fish
  • Gourami
  • Otocinclus Catfish
  • Platy Fish
  • Angelfish
  • Swordtail Fish
  • Khuli Loach
  • Guppy Fish
  • Rummy Nose Tetra
  • Flowerhorn
  • Neon Tetras
  • Siamese Algae Eater
  • Hatchet Fish
  • Betta Fish
  • Silver Dollar

Varied Pleco Diet

Offer a variety of food with protein, fiber and vitamins. There are specific blends of sinking pellets, rounds or wafers meant for plecos but you can also introduce the following foods 2-3 times a week:

  • zucchini
  • sweet potato
  • melons
  • lettuce
  • kale
  • celery
  • spinach
  • cucumbers
  • bloodworms
  • brine shrimp

Water Parameters

Your plecostomus could be hiding because the water quality is suboptimal. Ensure that your water quality stays near the range below:

  • Water Temperature: 74-80° F
  • pH: 7.0-8.0
  • Alkalinity: 3-10° dKH (54 ppm to 180 ppm)
  • Nitrates: Less than 40 ppm
  • Nitrites and Ammonia: 0 ppm


The plecostomus is a shy, reclusive and primarily nocturnal fish. They like hiding in dark areas, planted spaces and the corners of your tank. A hiding pleco may not mean that your water is off or that they are sick. Make sure they are getting plenty to eat and check their skin, gills, eyes and fins to make sure they look like their usual selves.

Move things around slowly if you want to see your pleco more often or stay up through the night if you wish to see them more active. Just kidding. We all need our rest. We hope your resting plecostomus comes out to say hi to you more often.


Thanks for visiting HelpUsFish.com and we hope to see you again for another article on Plecostomus or any other marine life that interests you. 

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.