Do Plecos Eat Fish? (5 Reasons Why Plecos Attack Other Fish)

Pleco searching for other fish to eat

Plecos are popular for their peaceful temperament and are favorites among aquarists to keep in community tanks. But do plecos eat other fish?

Plecos don’t eat other healthy fish. They’re opportunistic scavengers who eat decaying fish that sink to the bottom of the tank. They usually stay away from other fish in the tank. However, plecos may become aggressive and attack other fish if the living conditions in the aquarium aren’t conducive.

Let’s learn more about this in detail.

Are Plecos Friendly Toward Other Fish?

Plecos are friendly toward other fish. They usually don’t bother their tankmates unless the living conditions aren’t conducive.

However, plecos aren’t social fish like guppies.

They’re rather shy and don’t like to interact with other fish; they prefer to stay alone.

Plecos are also docile and get along well with similar temperament fish.

Some of the compatible tankmates for plecos are guppies, mollies, platies, gouramis, swordtail, corydoras, etc.

Although plecos are friendly toward other fish, male plecos are intolerant toward their kind.

So you can’t house multiple plecos together in the same tank.

Why Do Plecos Attack Other Fish?

Plecos attacking other fish of their kind is common as they’re territorial toward each other.

So many aquarists don’t house plecos together.

Instead, plecos are preferred in community tanks.

However, they can show signs of aggression and attack other fish as well due to numerous reasons.

Given below are the five main reasons why plecos attack other fish in the tank.

1. Stress

Stress is one of the primary reasons for aggressive behavior in fish.

Plecos are docile and don’t attack or bother other fish unless the living conditions aren’t favorable.

Stress can occur due to less space in the tank, constant bullying from aggressive tankmates, poor water quality, unfavorable water parameters, illness, food scarcity, etc.

A stressed pleco is more likely to attack other fish as it’s in discomfort.

2. Food Scarcity

All fish need adequate food to thrive. If the food is scarce, plecos can turn hostile toward other fish.

Plecos will start competing for the limited food supply. They will also look upon other fish as a threat to their next meal.

Competition for food can encourage plecos to attack other fish during feeding time.

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3. Overcrowding

Pleco in an overcrowded tank

Overcrowding is one of the significant reasons for plecos to attack other fish.

Some pleco species like common plecos grow pretty large and need ample space to move freely.

Shortage of space can turn plecos aggressive, and they may start to attack other tankmates.

Once mature, plecos don’t like to share their space with fellow tankmates.

So plecos can get territorial and attack other fish if they encroach on their territory.

Another downside of an overcrowded tank is less oxygen level, which further leads to stress and attacks on other fish.

4. Parental Instincts

Plecos can get aggressive during the breeding season.

They’re known for their parental care and take care of their young ones till they become independent.

Male plecos, in particular, are highly protective of their eggs and offspring.

So if he sees other fish trying to eat the eggs, the male pleco will attack the fish.

5. Illness

Illness is another potential reason for plecos to attack other fish. A sick pleco is usually distressed and prefers to remain on its own.

When other fish try to come near the sick pleco, it can look upon them as a threat.

The sick pleco can then attack the intruding fish in self-defense.

So it’s crucial to constantly monitor the health of plecos and provide appropriate medication if they fall sick.

Do Plecos Eat Fish Fry?

Plecos usually don’t eat any live fish. So they don’t chase the fry and try to eat them.

Plecos will eat the fry only if they’re hungry and don’t find any food around them.

In such instances, if they find fry around them, they may eat the fry to satiate their hunger.

Similarly, plecos don’t eat their own fry.

However, the male pleco can sometimes eat its fry if it’s stressed or the food is scarce.

But it won’t completely decimate the fry.

Which Fish Can’t Live With Plecos?

Plecos are compatible with many fish due to their peaceful temperament.

They make serene and pleasant tank inhabitants when away from other plecos.

However, you should avoid keeping the following fish with plecos for the sake of safety:

  1. Avoid aggressive fish like cichlids, crayfish, etc. that can bully the plecos.
  2. You shouldn’t house goldfish with plecos as the plecos can suck the goldfish slime when hungry or underfed.
  3. Don’t keep bottom-feeding fish that are faster than plecos as they will compete with the plecos for food, which leads to stress.
  4. You should also avoid keeping other plecos as tankmates as plecos are highly territorial toward each other.

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Are Plecos A Good Fish To Keep?

Plecos are one of the best fish for beginners and expert aquarists as they’re easy to care for and hardy.

They’re an excellent choice to clean the tank as they’re natural scavengers.

Plecos help keep the algae bloom in control and consume any uneaten fish food that can contaminate the tank water.

They’re also good companions in a community aquarium due to their peaceful nature.

The only downside of plecos is that some species like common plecos can grow pretty large and quickly outgrow the tank.

However, several pleco species like bristlenose plecos don’t grow to a substantial size and are a good fit for any aquarium.