Plecostomus (commonly known as a pleco) are great fish for your family’s aquarium for many reasons. First, they are easy to take care of. They are not picky and the only thing they require is a lot of water to swim in. They can save you money by not needing an expensive filter. The Plecostomus does not need a fancy filter because they are the filter eating up everything at the bottom of your aquarium. Third, they are very low maintenance. 

They are not very active and will spend most of their time hanging out at the bottom of the tank. They have a pleasant disposition. For the most part, they are not as aggressive as other types of fish and they do not nip at other fish.

A Plecostomus isn’t a fish that many think about when you’re looking to add a new member to your aquarium. But they really should be because they are a great fish for even the most experienced aquarium owner. 

Plecostomus are a species of sucker fish native to South America, and they are like a vacuum at the bottom of your aquarium. They do a lot to keep your aquarium clean and keep all the bad waste chemicals to a minimum between water changes. They do a lot to help keep the overall health of the other fish high.


Information about Plecostomus

  • Average Length: Up to 15 inches
  • Scale Colors: Gray, Green, White and Black.
  • Attention Needs: Low
  • Good tolerance to Heat and Cold: Yes
  • Good Pet: Yes!
  • Good with Other Plecostomus: Yes but their large size makes it difficult to keep them together.
  • Good with Other fish species: Yes
  • Suitable for First-Time fish Owners: Yes
  • Health Concerns: They tend to have Cloudy Eyes and Ich
  • Allergies: None
  • Average Life Span: 10 to 15 years

Physical Appearance of Plecostomus

Plecos have an elongated body with large pectoral, dorsal and tail fins. The dorsal fin has seven soft rays and one coarse ray while the anal fins have 3 to 5 soft rays and one coarse ray. The tail fin is shorter at the top and longer at the bottom. The dorsal fins also have spines on them.

A special feature of the Plecos is that they have large bony plates that cover their bodies. Because of this, they are often called ‘armored catfish’. The bony plates along with the spines on their fins act as armor as they help to protect the Plecos from predators in the wild. 

These fish have a large head with a sucker shaped mouth, often termed as ‘suckermouth.’ The unique shape of the mouth allows them to breathe, feed and attach themselves to surfaces at the same time. It helps them to survive in a diverse range of conditions. 

Their eyes are placed high on the head with a unique membrane covering their eyes that helps to regulate the exposure of light into the eyes. 

There are hundreds of species of Plecos with several color variations like black, white and green. They can come in patterns like solid, striped or dotted. The most common Plecos have a gray color with a brown and sand-colored pattern or spots on their bodies.

The Plecos can grow up to 24 inches in their natural habitats but in captivity, they will mostly grow up to 15 inches.

When viewed from above, the females seem to have a rounder body while the males have a skinnier body. The females are larger than the males.

Temperament of Plecostomus

Plecos are nocturnal fish and will be most active during the night. They will spend days hiding behind the plants or caves placed inside the tank.

They are slow-moving fish who prefer to stay closer to the bottom of the aquarium. 

They do not act aggressively against other fish species. If they feel threatened, they will just swim away. 

Plecos also tend to be good tank mates but their large size is an impediment. They can grow up to 15 inches long, making them one of the bigger freshwater fish you can own. The best way to keep them is making sure their tank is large enough for not only them, but all the other fish you plan to have.

Some Plecos tend to be timid. For the first few days after introducing them to a new tank, they may spend a lot of time hiding between tank decorations or under plants. They may spend less time hiding a few days after introducing them to a new tank.


Best Habitat for Plecostomus

Plecostomus are native to South America and are found in a diverse range of conditions in the wild. Most of these fish live in fast-flowing streams and rivers that have a rocky substrate but some are also found in brackish estuaries. As mentioned before there are several species of Plecos and each may have their own needs. So do your research before setting up their tank. 

Plecos tend to attach themselves to tank walls. They can easily scratch the acrylic tanks with their spines and mouth, so a glass tank is recommended for them. 

Tank size

Plecos are just 2 to 4 inches long when they are young, so you can keep them in a small tank of 10 gallons. The size of the tank depends on the species you get. The smaller Plecos – Otocinclus will not grow more than 2 inches and can be kept in a 10-gallon tank even when they mature. Some species can grow up to 15 inches and will need a larger tank when they are fully matured. For example, Hypostomus Plecostomus will need a tank of a minimum of 100 gallons when they are fully grown.



The ideal water temperature for the Plecos is between 72 to 86° F. Most other fish that they will live with will live in the higher end of this range. Because they can handle such a wide range of temperatures you can house them with just about any other fish.

pH Level

The pH level should be in the range of 6.5 to 7.5. 


Plecos need a tank with subdued lighting conditions. Adding floating plants can help with this. The lights should not be on more than 8 to 10 hours a day. Adding a timer to your lights will help to maintain consistent lighting inside your fish tank.


Plecos like to feed on Algae so the tank should have a number of plants. Plants having broad leaves like Java Fern and Anubias are recommended because the fish can eat Algae right from their leaves. 

These fish like to sleep during the daytime, so they will need plenty of hiding places inside the tank. You can use overturned flower pots, caves, or hollowed logs to create hiding places for them.

The tank should also have driftwood because Plecos like to nibble on them.

Tank conditions

To simulate their natural water conditions, try to create a strong water current should be inside the tank. Using a canister filter will help create the current and also keep the water clean. The canister filter isn’t needed for actual filtering as the fish does a great job at this, it’s only needed for the current.

Plecos will mostly stay close to the bottom. They will also scavenge for food from the substrate. Using gravel or soft sand as a substrate for the tank will help the Pelcos to filter through the substrate and find their food.  

Tank Maintenance 

Water conditions like temperature, pH level, and dissolved organic compounds should be monitored daily. Make sure the water filters are running properly and are efficient at cleaning the water. You can use a water testing kit to check the tank conditions.

Plecos are natural algae eaters and they will also eat decaying plant matter or dead fish that fall to the bottom. With them eating all of this, the aquarium will stay cleaner longer.

A 10 to 25 percent water change should be performed every other week.


Best Tank Mates for Plecostomus 

Young Plecostomus are community fish. They are peaceful and will not act aggressively with other fish species. Plecos are nocturnal and mostly active during the night.

Popular tank mates for Plecos are:

Avoid keeping Angelfish and Discus with young Plecos as they can nip at them. Smaller fish species that can fit in their mouth should also not be housed with them as Pelcos can eat them.

A major concern while deciding on a company for them is that they will get very large and outgrow other fish in the tank. Ideally, it is recommended to house them in a separate tank once they outgrow others. For the same reason, more than one Pleco should not be kept in a single tank because they will need a very large tank! 

Health Issues

Signs of a healthy Pleco are:

  • Clear eyes
  • Will have the ability to attach to glass or rocks
  • Remain close to the bottom
  • Eats actively
  • Has bright coloration.

Always check your fish for the above characteristics before buying them. An unhealthy fish can spread contagious diseases to other fish in the tank and also impact the water quality. 

Some common diseases found in the Plecos are listed below.

Cloudy Eye

As the name suggests the fish will have a whitish or greyish cover in their eyes. It will impact their visions and you may see the Plecos swimming in an unusual way. Some may also have a faint coloring on their body. Cloudy Eyes are usually a result of poor water quality and improving the water conditions will help to take care of the disease.

As you can guess by the name of the illness, the fish will have a white or grayish obstruction in their eye. Obviously this makes it difficult for them to see clearly. Because of the number of different reasons for the cause, it can be difficult to know what the cause is.


Trauma to the eye is the main cause for healthy fish to have this condition. The problem is that it can be difficult to know that this was the cause. Sometimes trauma to one eye can result in both eyes becoming cloudy. So while this is the main cause, you should come back to it after exploring other things that you can test for.

The next most likely cause is poor water quality. The water in your aquarium should be checked regularly to make sure that it’s both clean, and that invisible contaminants are not building up.

Diet seems to be the next most likely cause. Review what your fish should be eating and make sure that they are eating enough. Fish that get a well balanced diet are much less likely to be sick than fish that are low on some vitamins or not eating what they need.

Ich Disease

Ich is one of the most common diseases found in Freshwater fish. The disease is caused by a parasite that affects the gills and fins of the body. Poor water conditions and stress are major reasons that can lead to the fish catching this disease. When a fish becomes infected with Ich, it tends to rub against hard objects such as decorations, rocks and the substrate.

Symptoms include white spots on the body, breathing difficulty and fish rubbing against hard surfaces. In comparison to other fish diseases, these symptoms make it easy to identify if your fish is infected. 

A major concern is that this disease is highly contagious and can easily spread to other fish in your aquarium. If not treated early on, it can even cause respiratory issues. 

Treatments include slightly increasing the water temperature, adding medication to the tank and performing a large water change. If you have a community fish tank then it is suggested to move the infected fish into a quarantine tank and then treat them.

fish flakes

Feeding Plecostomus 

Many pet stores sell Plecos as ‘algae eaters.’ While they do eat algae, this is not the only thing that they need to eat. Leaving them without food can lead to starvation or even death. 

Depending upon the specific species they can feed on smaller fish, crustaceans and invertebrates. Some Pelcos may also prefer to feed on wood.

An ideal diet for most Pelcos should consist of algae and vegetables. You can feed them algae rounds, wafers, earthworms or dry food. 

Vegetables like zucchini, spinach, lettuce, cucumbers and shelled peas can also be given to them. The vegetables should be peeled and finely chopped. Driftwood should also be kept in the tank as some Pelcos will feed on that. 

They should be fed daily. If you are giving them raw vegetables, anchor them to the bottom of the tank.

Remember that Plecos are nocturnal and will mostly eat at night. While feeding them, keep in mind that they may not come out at once to eat the food that you give them. They are timid and like to eat the food when no one is around.

Related Questions:

Are Plecos good for beginner fish tank owners?

If you can accommodate them in a spacious tank, then they can be a good fish for you, even if you are a  beginner. Plecos are natural cleaners that reduce the maintenance needs for your tank. They will eat the algae and decaying organic matter in the tank. All you need to provide for them is a large fish tank of at least 100 gallons

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