Do Pleco Eat Dead Fish? Facts You Didn’t Know

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Plecos are bottom-dwelling scavenges that virtually anything they can find on the substrate. But do they also eat dead fish?

This is not only a legitimate question but a concerning one as well, given the implications. We’re talking about several aquarists raising awareness about plecos eating other smaller fish.

Do they eat their tank companions, dead or alive, and do plecos use to eat other fish at all?

Let’s discuss it, shall we?

Will Plecos Eat Dead Fish?

Yes, they will. Plecos won’t let anything to waste. If there are dead fish around them, plecos will eat them, provided they are small enough for that.

If the fish are too large, the pleco may struggle a bit with the meal but will get it done.

The catfish will use its suction-based mouth to break the dead fish into smaller pieces.

This is only possible if the fish has been dead for some time and the decomposing process has begun.

This makes the fish’s flesh easy to break but also makes its carcass more dangerous.

Is it Safe for Plecos to Eat Dead Fish?

There isn’t a clear answer to this question, as it depends. In general, it’s not dangerous for plecos to eat dead fish.

They do it all the time, both in the wild and in captivity. The problem is that this seemingly natural behavior can backfire and strike your pleco down.

We’re talking about why the fish died and the time window when the death occurred.

Here’s what to know in this sense:

  • The cause of death – Fish die for a variety of reasons, including chemical poisoning (ammonia, chlorine, heavy metals, etc.), parasites, bacterial infections, etc. Others simply die of old age or due to violent interactions with other tankmates, but they’re otherwise healthy. Or they were until the moment they died. The latter are safe to eat, but the former are not. Since you cannot know what caused the fish to die, I recommend denying your pleco the fish meal. Remove the fish’s carcass immediately, as this is the wiser and safer choice, in my opinion.
  • The time of death – Even healthy fish can turn foul with time. This is due to the bacterial activity that contributes to the decomposition process. Dead fish will accumulate bacteria fast, which will release ammonia as a byproduct. The fish’s carcass will soon become unfit for consumption and may cause the pleco to fall sick upon eating it.

In short, there’s nothing you can do to prevent your pleco from eating dead fish when you’re not around.

But if you are, you should prevent that. Eliminate any dead or dying fish from the ecosystem and feed your pleco healthy and safe meals instead.

Should You Feed Dead Fish to Plecos?

Again, this only depends on the dead fish itself. It’s not okay to feed plecos fish that have died due to unknown reasons.

But it is okay to feed them healthy and freshly-deceased fish. The pleco will use the extra protein wisely.

With this said, you shouldn’t feed your plecos too much animal protein, given that this is an herbivorous animal.

Plecos require minimal animal protein, as they much prefer detritus, algae, plant matter, and veggies over anything else.

Will Plecos Kill and Eat Other Fish?

They might do that, yes, but it’s extremely unusual behavior. Plecos are peaceful herbivores that will avoid conflicts and don’t exhibit predatorial behavior.

I would say that there are several instances where plecos will kill and eat other fish:

  • They will consume fry – Plecos are avid scavengers that will consume anything that moves (or doesn’t) on the substrate. This includes algae and plant matter, fish eggs, insect larvae, bloodworms, and even fish fry. They may also catch the fry from the water column if they come too close to them. The fry are pretty much indistinguishable from any other micro creature that the plecos eat on the regular.
  • When stressed – Stressed plecos can become more aggressive and are even known to attack some of their tankmates on occasion. This behavior can lead to murder if the target fish is considerably smaller and weaker than the pleco. To prevent this, assess the situation and learn what’s triggering your pleco’s foul temperament. Removing the triggers will usually correct the problem fast.
  • During mating – Plecos are notoriously violent during the mating season when they compete for females. In this case, the violence is particularly aimed towards each other, but they can also attack other nearby fish in some cases. The situation is easily preventable by investing in a breeding tank and relocating your catfish during the breeding phase.
  • When starving – Starvation can turn even the most peaceful and docile fish into a killer under the right circumstances. The same stands true for plecos which are notoriously underfed due to their reputation as proficient scavengers. Unfortunately, though, plecos can’t survive on scraps alone. They also require proper meals to supplement their nutritional plan and remain full and healthy.

In short, if you notice your pleco attacking and eating other fish, know that something’s not right.

Investigate the situation further to detect the reasons behind the pleco’s aggressive behavior and seek adequate corrections.

Conclusion

Plecos are calm and peaceful catfish that shouldn’t cause any trouble in the tank. They make for great community fish thanks to their easygoing attitude and scavenging role in the ecosystem.

Unfortunately, even the peaceful pleco can sometimes go haywire. When that happens, it pays to assess the situation objectively and look for proper solutions asap.

avatar I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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