Plecos – Everything You Need to Know About Them

Plecos, plecostomus

Plecos are a common choice for fish keepers as they aren’t high maintenance. There are over 150 different species, but the most popular are the common Pleco and Bristlenose Pleco. These nocturnal, freshwater catfish can be found in the rivers and streams of South America.

Since they’re nocturnal, you won’t get much out of them during the day. Although they’re not aggressive fish, most Pleco species get very big and are territorial towards other Plecos. They’re excellent community fish and, being bottom dwellers, work well with most community fish.

Take note: Plecos are often sold as algae eaters. In reality, their dietary requirements are more complex; continue reading to learn more.


Plecostomus; full body

The Pleco has a long body that can be anywhere from 4 to 24 inches long when fully grown. It has rows of bony “armor” plates and large fins. The dorsal fin of this fish has seven soft rays and one coarse ray, and its tail fin is moon-shaped.

Plecos have big heads with small eyes almost on top of them. The distinguishing feature of this fish is its mouthparts. Plecos and other Loricariids have highly mobile upper jaws; their lower jaws have unique teeth that help scrape algae off rocks and driftwood. You’ll also see that their lips are perfectly evolved to suck onto surfaces.

Many Pleco species are brown or gray with sand-colored patterns, though many species have more vibrant colors and patterns.

Temperament and Behavior

As mentioned before, Plecos are nocturnal, so you aren’t going to see much movement from them during the day. They’ll mostly stay among plants or rocks in your tank, and they love hiding in caves and under rocks or driftwood. Your Pleco might come out to feed, but this will mainly happen at night.

When your Pleco becomes active, you can watch it suck up algae from your tank. They move slowly across rocks and even attach their sucker mouthparts to the glass of your tank. Please note that algae shouldn’t be the only thing they eat. Plecos are omnivores and, therefore, can’t be kept only as algae eaters.

Plecostomus are generally peaceful, but you should always make sure adults have big enough accommodations. If they’re happy, they make amazing community fish.

Nonetheless, adults can sometimes learn to suck the slime layer off other fish. This is extremely damaging and can even result in the removal of whole scales! However, this usually only happens if your fish are malnourished.

Popular Plecostomus Species

Not all 150 Pleco species are suited for aquariums. The species that are popular among aquarists are listed below. Often Pleco species are sold under their “L” numbers. An “L” number is a designated code or number that is used to identify Locariid catfish.

Gold Nugget Pleco (Baryancistrus xanthellus)

Gold Nugget Plecostomus

The Gold Nugget Pleco is one of the more sensitive and “fancy” Pleco species. This stunning black-and-gold spotted Pleco isn’t as tolerant of poor tank conditions as some other catfish. Gold Nugget Plecos reach about 8 inches in length and prefer a sandy substrate.

This species of Pleco is the most territorial and will go for any other Pleco in the tank. But, it will ignore almost all other freshwater fish you introduce. Gold nugget Plecos are often still classified under the ‘L’ number. L018, L081, and L177 are the three different types available in pet stores.

Zebra Pleco (Hypancistrus zebra)

You can only find this Pleco in one place in the wild, the Xingu river in Brazil. They can be a little bit more challenging to get hold of, but their unique zebra pattern makes them a popular choice for fish enthusiasts. Zebra Plecos are a dwarf species and only grow up to 10 cm, they also have slightly bigger eyes than other Plecos.

Unlike many other Plecos, these fish don’t eat algae. Zebra Plecos need a protein-rich diet and eat a small number of fresh vegetables such as cucumber slices. Because of the size and little mouth, they don’t have to be kept alone but won’t do well with aggressive fish.

Clown Plecos (Panaque maccus)

Clown Plecos are some of the easiest Plecos to keep because of their natural habitat. These fish naturally occur mainly in Venezuela and have been found in Columbia too. The primary habitat of clown Plecos is in the Apure and Caroni River basins, which are littered with driftwood and vegetation. These Plecos love feeding on driftwood and don’t mind muddier water.

Clown Plecos have a distinctive pattern of black and orange or yellowish bands. They’re much smaller than your average Pleco, reaching only three or four inches. You should feed them a well-balanced diet of plant-based foods, algae, driftwood, and proteins. These Plecos can be kept with any other non-aggressive fish and rarely pay any attention to them. You should, however, be careful about keeping two males in the same tank.

Royal Plecos (Panaque nigrolineatus)

Royal Plecos are found in the Amazon and Orinoco Rivers as well as tanks all over the world. There are many types of Plecos for sale; the most common type is L27a or L190. Other Royal Pleco types for sale are L27, L27c, L330, L191, L418, L90, and L203. Each of these types has slightly different physical characteristics.

Most Royal Plecos grow to 16 inches long, but the Black Royal Pleco can reach 24 inches. These fish are very colorful with light grey bodies and grey or orange line-type patterns, bright red eyes, and golden dorsal fins. Because of the heavy armor plates, these fish can’t swim as well as others.

The Royal Pleco is herbivorous and, like the Clown Pleco, includes driftwood as an essential part of their diet. They also eat algae-based foods and fresh vegetables as treats. It is recommended to keep royal Plecos with slow-moving fish and avoid keeping them with other catfish. Because of their size, it’s best to keep them in their own tanks or big aquariums with fish that stay closer to the surface. It is also best to avoid putting any plants in with these fish.

Snowball Pleco (Hypancistrus inspector)

Snowball Plecos are black or reddish colored fish with many white or yellow polka dot “snowballs” on its body. It comes from the Rio Negro, which is the world’s largest blackwater river. This type of Pleco is an omnivore but not a good algae eater, be sure to feed it a balanced diet of proteins and plant-based foods.

These fish need more caves and hiding spots than most because of their natural environment, and they thrive in stronger currents and higher oxygen saturation. They’re a peaceful species, and you can keep them with most other peaceful fish species.

Sailfin Pleco (Pterygoplichthys gibbiceps)

Sailfin Plecostomus

Sailfin Plecos (also known as Leopard Plecos) are found in many countries in South America. They eat a massive amount of algae and can keep big tanks clean. These fish can reach 19 inches, and many people struggle to keep them in home aquariums.

The sailfin Pleco has a consistent spotty pattern that is hypnotizingly beautiful. Primarily these Plecos will be oranges and browns with the brightness of these colors vary for every fish. Sailfin Plecos have mostly the same shape as other Plecos, with the exception of their huge dorsal fin (which is where they got their name).

Feeding these fish is like any other Pleco; they’re omnivores but will rarely eat meaty foods. Sailfin Plecos are fairly mellow fish but can get territorial with their own species. They’re also known to show aggression if other fish bother them while feeding. Other than that, you can even keep significantly smaller fish with them as they won’t be eaten.

Bristlenose Pleco (Ancistrus sp.)

The Bristlenose or Bushynose Pleco isn’t technically part of the Plecostomus group. Though, they’re still referred to and sold as Plecos and are often even more popular than the common Pleco. These fish are smaller than average Pleco and much easier to keep. They grow only to about 5 inches and have a unique appearance.

Bristlenose Plecos can be found in black, brown, grey, and you can even buy an albino Bristlenose Pleco. They have lighter spots on their bodies. The thing that makes them so unique is the tentacle-like growths that sprout from their head. They use these to detect movement in the water and help find insects.

Bristlenose Plecos are not as shy as other Pleco species but aren’t too active either. They will mostly stay motionless at the bottom of the tank or on the glass. These fish are not aggressive, but you should be cautious about putting your fish in with another male or a similar-sized Pleco.

These Plecos are mostly herbivores but are not good algae cleaners.

How to Take Care of Your Pleco

Bristlenose Pleco

Tank Requirements

The natural habitat of Plecos allows them to handle many different habitats and setups. This group of fish is massively diverse, and many species need special care. Always research the species you have chosen so you can set up the best habitat for your new friend.

When you first buy these fish, they will usually be around 4 inches long, but don’t be fooled. Most species of Pleco, such as the Sailfin Plecostomus, grow to approximately 16 to 24 inches and would need a 150-gallon tank at least. Smaller species, like the Bristlenose Plecostomus, can survive in 70 or 80-gallon aquariums.

When setting up an aquarium for any fish, you want to mimic their natural environment as best you can. As you have already learned, Plecos live in the shallow streams and rivers flowing through South America’s tropical forests. How can you mimic that in your aquarium?

Plecos enjoy rocky or sandy substrate depending on the species and their natural habitat. Be sure to add big rocks and hiding places as they will mostly hide during the day. Most Plecos prefer lots of plants and driftwood to nibble on and hide in. Driftwood is an essential part of any Pleco tank. Not only does it promote algae growth and provide hiding places, but a few species of Pleco can digest this wood and need it in their diet.

The Plecostomus lives in fast-moving streams and rivers, so you must make sure the water is well filtered. They also like strong currents, but it’sn’t necessarily required. They’re tropical fish and thrive in temperatures between 70℉ and 86℉ and a pH between 6.5 and 7.5.

Plecostomus Diet

Many stores and breeders sell Plecos as algae eaters, but this isn’t necessarily the case. Every species of Pleco has unique feeding habits and needs. As mentioned before, please research the requirements of your Pleco before you decide to buy one.

While all species of Pleco eat algae, most of them are omnivores and need a lot more variety. Some even have special enzymes that allow them to digest wood.

The recommended diet of a Common Pleco or Bristlenose Pleco should include algae, vegetables, and the occasional protein-rich snack.

Vegetables you can feed you Pleco include lettuce, zucchini, cucumbers, peas, and spinach. They can eat these fresh or lightly blanched. Vegetables and driftwood in the tank help promote algae growth and give your Pleco the amount of fiber they need.

You can give your Pleco live foods such as bloodworms, larvae, crustaceans, or earthworms for protein. Plecos seem to prefer worms because they sink and are easier to suck up.

Because Plecos are mainly nocturnal, it’s best to feed them right before turning the lights off at night.

Tank Mates

It is recommended for beginners to keep most species of Plecostomus in their own aquariums. There are a few reasons for this, one being their size. The average Pleco can reach about 16 inches long or more. This makes it very difficult for anyone except advanced fish-keepers to keep them well in large community tanks. But, if you can handle taking care of a big aquarium they won’t bother your other fish

Another reason to keep a Pleco alone is they can unintentionally hurt your other fish. Because of their placid nature, they can sometimes start sucking on the scales of other fish. While this might look cute, it can be extremely harmful to your fish, and they can lose scales to the Pleco. As mentioned before, this only happens if the Pleco is lacking protein in their diet.

If your Pleco is young or a smaller species, you can keep them with most non-aggressive fish. For aesthetics and food distribution, it’s better to keep them in a tank with fish that don’t spend a lot of time at the bottom of the tank. Although Plecostomus are usually anything but aggressive, it’s best to stick to one in an aquarium, as they can get territorial.

Some great tank mates for your Pleco are Tetras, gouramis, cichlids, or any other community fish. Plecos will very rarely go for other fish even if they’re much smaller. This will only happen if the fish is dead or dying, or if the Pleco is extremely malnourished.

Plecostomus Diseases

While Plecos are relatively hardy fish, there are a few diseases you should look out for.

Ich, Ick, or white spot is a parasitic disease that is common in freshwater fish. The first visible sign of this disease is small white spots that form coarse crystals on your fish’s fins and body.

Fish fungus shows as a white or gray cottony growth on your Pleco. This disease is usually a secondary infection and is caused by oomycetes. Dropsy and Fin Rot are bacterial infections that cause bloating and loss of color in your fish. A possible cause of this infection is malnutrition or dirty water.

Plecos sometimes get hole in the head or lateral line erosion. This disease has no known cause, but some specialists theorize that poor water quality, malnutrition, and overexposure to carbon could have this effect. Typical symptoms include holes or indentations in the head. Another disease Plecos can get is pop-eye, which causes their eyes to protrude out of their skulls. It’s a bacterial infection that can be treated with vitamin supplements and tetracycline*

If you notice anything strange about your fish, you should take it to get treated as soon as possible. The symptoms and diseases mentioned here aren’t the only ones that can plague your Pleco, and you should always keep a close eye on all your fish. To avoid these problems, keep your aquarium clean and feed your fish daily. Be sure to do regular partial water changes. You should also know what foods your fish need and how regularly to feed them to keep them at optimal health.


Plecos are beautiful, medium-maintenance fish that any fish enthusiast will love. Plecostomus need warm, oxygen-saturated water in a tank with lots of hiding places. Most pet stores sell them as algae eaters, but their diets vary and are unique, with some even including driftwood.

The most popular species is the Bristlenose Plecostomus, but there are a variety of colorful species of all shapes and sizes. Each species comes from a different area in South America and therefore has different needs. As always, do research on your Pleco – make sure you know how big it’s going to get and precisely what its dietary requirements are.

It’s best to have a tank just for your Pleco if you don’t have the equipment or experience to keep a big tank clean. Smaller species or juveniles can be kept with other fish but can be harmful if they get hungry or territorial. With the right filters, care,  and food; Plecos can thrive in a bustling community tank and are beautiful additions To your aquarium.

Johanan Viljoen

Johanan Viljoen


Johanan is a lover of animals, and fish-charmer of note. In other words, he finds fish charming. He also has over 10 years of experience in the hobby.