The Bristlenose pleco is typically an easy-going freshwater fish. The Bristlenose pleco is a nocturnal species and prefers shallow waters with lots of driftwood and plants where it can seek refuge.

Bristlenose plecos have become a popular species due to their easy care and maintenance. Now, you’re probably wondering: how many Bristlenose plecos should I keep in a 55 gallon tank?

The short answer is that you shouldn’t keep any more than two in a 55 gallon tank.

How Many Bristlenose Plecos in a 55 Gallon Tank?

One of the main reasons you should keep 1-2 is because Bristlenose plecos are known to produce a ton of waste output. This is why many aquarists typically put 1-2 pleco for every 55 gallons.

If you have a tank, that’s more than 55 gallons, then a good rule to follow is to add 10 gallons for each additional pleco.

Although plecos are considered being docile and peace-loving, they can get a bit hostile and territorial. You need to be careful regarding what other fish to keep with them.

Between the plecos’ massive bio-load output and aggressive behavior, some fish may struggle to live with them.

How Many Gallons Does A Bristlenose Pleco Need?

As mentioned above, 55 gallons is a good size to keep 1-2 plecos. Although if they’re still juveniles, you can get away with keeping one in a 20-gallon tank.

Now, it’s time to learn a bit more about what makes Bristlenose plecos unique.

A fully grown Bristlenose pleco can grow up to 5 inches long in the tank. However, when in the wild, they can reach up to 8 inches in length.

Females can usually be identified as being larger with a rounder appearance compared to males.

Some Bristlenose plecos have been known to live up to 10 years, although in the wild this can be a lot longer.

With the proper care and management, you should expect a pleco to live for around 5 years.

How Many Bristlenose Plecos Can Be Kept Together?

Bristlenose plecos make great fish for beginner or inexperienced aquarists. Not only are they laid back, but they’re also relatively easy to care for.

While they’re considered as being typically solitary fish, Bristlenose plecos enjoy the company of other plecos. You just need to make sure there’s enough space for all of them to swim around comfortably.

Remember to add 10 gallons per extra pleco, after 55 gallons. Here are some tank requirements you need to keep in mind to make sure your plecos are happy.

Tank Decor
As Bristlenose plecos are nocturnal, they need objects to hide behind during the day. Some examples include adding caves and large rocks.

It’s also recommended to keep some live plants. The best types of plants are hardy, fast-growing, and strong enough to remain rooted in the substrate, as plecos are always foraging for food.

Bristlenose plecos also prefer natural wood, especially bogwood.

Here are some other types of wood you can add to your tank to make your Bristlenose pleco happy:

  • Redmoor Root Wood
  • Jangle Wood
  • Manzanita
  • Marsh Root
  • Cholla Wood

Filtration System
Bristlenose plecos produce such a massive amount of bio-load, which means that you should have a hard-wearing filtration system that is much more vital.

This species are hardy creatures and used to high-current waters in the wild. So, they need to rely on good filtration and oxygenation to stay healthy.

Even if you intend to keep 1 Bristlenose pleco in your 55 gallon tank, having a reliable filtration system is a must. It’s a great way to ensure that your tank’s water is clean and has optimal oxygen levels.

You should consider picking a high-powered filter, preferably with an oxygen intake hose.

A filter like this will create the water flow that Bristlenose plecos enjoy. In addition, the oxygen hose will ensure that the water has the right amount of oxygen levels needed for them to thrive.

Regular Feeding
Bristlenose plecos are mainly herbivores, so they spend most of their time foraging for algae.

It’s unlikely that your tank will have enough algae needed to sustain their consistent food supply. So, their diet needs to be supplemented with a range of foods each day to help maintain their health and development.

One way to ensure that a Bristlenose pleco is getting the nutrients they need is to keep an eye on its color patterns. Bristlenose plecos are known for their striking coloration. So, if you notice their coloring becoming dull, it could mean they’re not getting the balanced diet they need for optimal health.

You can feed each pleco about 1–2 pieces of wafers or a small slice of vegetables once a day.

It’s important to remember to remove food remains as quickly as possible. Doing this will prevent waste pile-up, which leads to unsuitable water conditions. Plus, it stops the pleco from overeating and getting sick.

Remember, Bristlenose plecos enjoy grazing on the substrate at the bottom of the tank. So, you should pick foods that can sink to the bottom of the tank, such as:

  • Algae wafers
  • Bloodworms
  • Fish flakes
  • Blanched vegetables like spinach, peas, carrots, and lettuce
  • Spirulina wafers

What Behavior Should You Expect?

Many male Bristlenose plecos can be peaceful together. They usually stay out of each other’s way, enjoying swimming along the bottom of the tank.

They also love to hide behind plants or in pieces of driftwood.

You’ll notice your Bristlenose plecos becoming more active at night. Although their night-time activities aren’t that much different from their morning routine, as you’ll still find them burrowing in the substrate.

One thing that they do more at night is grazing for food. They spend a lot of time nibbling on algae growths for hours on end.

Tank Requirements Water Conditions
The good news is that Bristlenose plecos are considered as being quite hardy. They do very well in a wide array of water conditions.

However, in order to maximize their lifespan and ensure they’re in good health, focus on the following:

  • pH levels: between 6.5-7.5
  • Hardiness: 20-25 general hardness (GH)
  • Temperature: between 60℉-80℉
  • Water hardness: between 6-10 carbonate hardness (KH)
  • Tank Mates that should be avoided

While Bristlenose plecos are generally calm and easy-going, this mightn’t be the case with the entire population of the tank.

Some Bristlenose plecos can get pretty aggressive toward one another as well as towards other smaller, fin-nipping fish, like Corydoras. In some cases, the Bristlenose plecos can even attack their unsuspecting tank mates without any apparent reason, almost killing them.

Here are some examples of some of the fish that don’t get along with plecos:

  • Guppies
  • Goldfish
  • Gouramis
  • Mollies
  • Neon tetras
  • Platy fish