Goldfish and pleco catfish: two of the most popular fish kept in the aquarium hobby. Goldfish are kept for their hardiness and color, while plecos are often bought to clean up the tank. This raises the question: can goldfish and plecos live together?

There isn’t a direct answer to this, because there are many parameters and aspects to keep in mind when considering this option. Goldfish and plecos have totally different temperaments and there are some reasonable differences in terms of care. Yet, in some cases, you can keep these to amazing species together!

Can a pleco live with goldfish?

It’s often said that these to fish aren’t a good fit in most aquarium setups, which is true. It’s however short-sighted to say that this means that they aren’t compatible at all. So are they compatible, and if so, what to look out for?

It’s not recommended, but certainly not impossible to keep plecos and goldfish together, but only in a spacious tank (>80 gallons). If your pleco is being fed a varied and nutritious diet, it will not harm the goldfish.  Goldfish prefer to live in colder water, though, which is not ideal for some pleco species.

Do plecos eat or suck on goldfish?

One of the biggest arguments for not keeping plecos and goldfish together is that plecos might suck on the slime coat of goldfish. You see, a goldfish has this slime-coat that protects it from diseases and possible harmful toxins. If you’re a fisherman you’ll probably know this, and it’s why to never touch a fish with dry hands because it might harm the fish’s slime coat.

Anyway, it’s this common myth that plecos will always viciously attack a goldfish or try and eat its skin at night.

Pleco catfish can harm a goldfish’s skin or suck on it. However, this is most likely the cause of it being underfed. Some plecos can get very big, so they will need a lot of food to be healthy. This also mostly occurs with big species such as the common pleco.

Many people don’t realize that when they buy a pleco in the pet store, it might get up to 15 inches in size. This is the case for the common pleco, a very popular species. They are omnivores and very hardy, which makes them grow super fast and get enormous.  

These plecos grow big, so a good amount of food has to be fed to them. Even though plecos eat algae, it’s a myth that they can survive on that. If it feels hungry or is starving, it will likely try and eat off your goldfish.

As stated above, this is mostly the case for common plecos. Smaller species like bristlenose or rubber lip plecos are more peaceful, and less capable of sucking onto the goldfish.

Will goldfish eat plecos?

Goldfish are herbivore fish and will not eat pleco catfish. Occasionally, goldfish might eat small fish fry, but plecos are usually too big to fit in their mouth.

Different pleco species and their compatibilty

Did you know that there are more than 150 registered pleco species? All of these have different requirements and temperaments. Here are four of the most common species listed, and how they get along with plecos.

Bristlenose pleco

This is one of the most popular pleco species in the hobby and it’s easy to see why. It’s very hardy and stays relatively small. This makes them a better choice for most people than the common pleco, and way easier to manage. Since they are smaller, they will also need less food, so the chances of them trying to eat the slime coat of your goldfish are minimal.

Bristlenose plecos are commonly available at most pet stores and grown males are easy to identify by their bristles.

Common pleco

A common pleco eating broccoli. Photo by Napolean_70

A common pleco is another popular pleco species. Unfortunately, this mostly comes out of unknowingness. When buying, they are a couple inches at max, but soon they will grow up to 15 inches!

Even though this species is very hardy, they need a 100 gallon (at least, 150 gallons to grow to their full potential) tank to be happy and healthy. On top of that, you will need to feed them a lot so they don’t starve. If it’s hungry, this fish may suck on the slime coat of goldfish.

If you do however have a big tank and are prepared to feed them a healthy diet, it’s possible. They are compatible in terms of temperature. Both goldfish and common plecos can live in temperatures of 70-74°F (21-23°C).

Rubberlip pleco

Photo by Suzy

This species is less known than the other species on this list, but it does make a good goldfish tank mate. They stay quite small (up to 7 inches), which makes them easy to feed.

It’s also quite hardy and it can live, just like goldfish in temperatures between 70 and 74°F.

Clown pleco

This species is often sold as Peckoltia vittata and has gained a lot of popularity. It’s the smallest species on this list, and also very hardy. The clown pleco eats driftwood as a part of its diet. Thus, it’s important to incorporate this in your setup.

Read further to know more about the tank setup, or read our article about why plecos need driftwood.

Zebra plecos

Zebra plecos are not a good species to keep with goldfish, because they need high temperatures to thrive (82-88°F). Goldfish on the other hand prefer lower temperatures. 

How to keep a pleco with goldfish

It’s important to carefully consider your tank setup to make sure it’s fully suitable for both the goldfish and plecos. This is often the part where many people get it wrong and which causes your plecos and/or your goldfish not being able to live together.

Choose a big tank

This blog isn’t about goldfish, but I do want to clear out a common misconception: goldfish cannot be kept in a 20-gallon tank. Did you know they can get over 15 inches long when kept in a pond? This is why goldfish should be kept in a tank that’s at least 40 gallons. Add another 10 gallons per fish you add. 

This means that if you want to add a pleco, make sure your tank is big enough for only the goldfish. I’d say that you can add one small pleco species (f.e. bristle nose plecos/clown plecos) per 5 gallons, on top of the 40 gallons.

When talking about the common pleco or other species that can get very big, a tank upwards of 140 gallons is recommended. In a 140 gallon tank, you can put one big pleco and 8 goldfish.

The ideal habitat / tank decor

There are a few things every pleco tank should have for it to be happy and healthy. However, with goldfish, it might get tricky.

As you might know, goldfish are carp. This means that their diet consists of plant-based materials. As a result, most plants aren’t safe with goldfish.

Well, that’s a small problem. You see, every pleco needs at least some plants in order to feel safe, happy and to be healthy. 

Luckily, there are a number of plants plecos love and goldfish will not eat. Here are a couple plants listed:

  • Anubias – This big-leaved hardy plant is ideal for many tanks, due to its ease to care for and unique appearance.
  • Java fern – Another very easy plant species. Just like Anubias, it grows on wood or stones and it’s very easy.
  • Cryptocoryne sp. – This plant grows in the substrate and needs medium lighting. Just like the former, it’s great for beginners and it looks great!

Water parameters

When talking about keeping goldfish and plecos together, many people argue over the water parameters. Why?

Goldfish like colder water temperatures and a higher pH(they also like living in ponds). On the other side, plecos live in the tropics of the Amazon rainforest and live in soft, warm water. 

Water temperature

The ideal temperature for goldfish are water temperatures below 74°F. Plecos on the other hand can live in temperatures from 72°F to 88°F for some species like zebra plecos.

So, before considering what pleco species to put in your tank, make sure the pleco can live in 72-74°F.

Other parameters

Both goldfish and most pleco species tend to do well on tap water. Tap water is however different for everyone, so here are the ideal water parameters for plecos and goldfish:

Goldfish

pH – 7-8

GH – 4-8 dGH

KH – 120-220 ppm

Plecos

pH – 6-7.5

GH – 4-8 dGH

KH – 70-180