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The Complete Guide To Caring For And Keeping Plecostomus

A master of disguise and a great tank cleaner to boot, the Plecostomus fish is a prehistoric-looking fish with some seriously cool natural traits. This fish is one of the most popular for home aquariums, possessing the unique ability to clean up excess algae.
Many people shy away from owning Plecostomus fish, believing that they will be too large – or too high-maintenance – for their existing tank set-ups. However, the opposite is actually true. Plecostomus fish can be raised by novice or experienced aquarium hobbyists alike, with minimal work and know-how required.
The Plecostomus fish is a great addition to any tank, getting along well with most other species and eating just about any kind of algae that they encounter. If you’ve been hesitating about your decision to purchase or your ability to care for a Plecostomus fish, consider our complete care guide to help make the transition just a little bit easier.

The Complete Guide to Caring for and Keeping Plecostomus


Plecostomus Origins

These tropical fish belong to the armored catfish family Loricariidae, aptly named for the rows of scales along their heads and bodies that look not unlike coats of armor. Plecostomus, or “plecos,” as they are commonly referred to, are found in their native range in northeastern South America in countries like Brazil, the Guianas, and Trinidad and Tobago.
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Plecos are often referred to as algae suckers or eaters, municipal fish, and suckermouth catfish. The name Plecostomus is often incorrectly used to describe similar catfishes, but they aren’t all the same. True plecos set themselves apart from the crowd based not only on their appearance, but also in their native range, eating habits, and other behaviors.

Plecos have found their way into water systems where they are not naturally found, probably due to irresponsible release by aquarium owners who have not been able to handle the plecos once it reaches full size. They have been recorded in places like Florida and Texas, where their populations have grown so out of control that they are regarded as invasive species.
In the wild, these fish prefer freshwater habitats on both the east and west sides of the Andes mountains. They are frequently found in fast-moving streams at all elevations, but can be found in other freshwater environments as well. Plecos have been found in brackish estuaries, acidic waters, mountain rivers, and even subterranean habitats.
They are not believed to be endangered or threatened in any way, although their populations have not been substantially studied for this purpose. Since they are not prized as food species, the only threats to their survival include capture for breeding in captivity and habitat degradation.

These fish are predominantly nocturnal, with some preferring to live in groups while others enjoying a more solitary existence. Because they live in fast-moving waters, they have the habit of adhering to objects when submerged, clinging tightly as they eat invertebrates, algae, and detritus. These omnivorous scavengers aren’t picky – while most will stick to plant matter and fallen materials, some species are more adventurous – even eating wood!

Plecostomus Appearance

Despite sharing several common traits, Plecostomus is a vastly dissimilar group. These fish can be found with all kinds of color patterns and body shapes. Some plecos have fins with spines., for example, while others have unique maxillary barbels.
All plecos have long intestines to help them process their mostly herbivorous diets, with taste buds that span their entire body. Other common traits include bony plates that cover their entire bodies, as well as ventral mouths. These mouths have small projections on the lips that help them feed.
These mouths are the plecos’ most famous features. Often described as a “suckermouth,” these mouths help the fish breathe, feed, and attach to the substrate via a suction method. They can both breathe and suction at the same time, a unique feature that allows them to survive in a variety of settings.
The Complete Plecostomus Care Guide 2The plecos fish has armor that covers almost its entire body, with the exception of its stomach and head. These are part of the fish’s defense system, as are the spines found on the dorsal and ventral fins. These spines are pushed forward whenever the fish perceives a threat. It also uses its spines to help wedge itself in crevices. In the wild, this prevents the fish from being swept away in a strong current.
There are several well-developed fins on the plecos, with the dorsal fin having one coarse ray and seven that are soft. The anal fin also has one coarse ray and three or four soft rays, while the tail fin is moon shaped.
Most plecos are relatively flat but long. Their head sizes are relatively proportional to the rest of the body, with each fish possessing unique Omega eyes. These eyes possess upside-down pupils, similar in appearance to the Greek letter O (hence the name). Their eyes dilate in ambient light and also have membranes to shade them from bright lights.
There are many different color variations and patterns, including polka dotted, striped, and solid. With colors ranging from black to white to green, there is no shortage of coloration options for the plecos you choose to put in your tank.

Types Of Plecostomus

There are hundreds of types of Plecostomus, with species ranging to fit any size or type of aquarium. As one of the most popular types of fish for the aquarium, Plecostomus are prized for their abilities to help keep your aquarium clean. Here are a few of the major types of plecos available for purchase in the fishkeeping hobby:

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Photo by Andy hunting
  • Zebra Pleco:

Scientifically known as Hypancistrus Zebra, this fish grows to about three inches in length. It is black and white, with head stripes running horizontally. It also has vertical body stripes. It is one of the more expensive varieties of plecos due to its stunning appearance. This fish is one of the smaller plecos, needing a tank that is only about thirty gallons or so in volume.

  • Gold Nugget Pleco:

This fish has a black body with gold spots. Its fins have thick gold edging, and it can grow to nearly nine inches in length. Scientifically known as Baryancistrus Xanthellus, this fish is a good option for beginning aquarium hobbyists. It needs a tank of about 50 gallons or more in volume.

  • Common Pleco:

The Common Pleco is dark brown to gray and has black markings. It is massive, growing to about twenty inches in length. However, this fish, Hypostomus Plecostomus, is affordable, with most starting at only $10 per fish. These fish need large tanks of at least 125 gallons in volume.

  • Snowball Pleco:

This fish, Hypancistrus Inspector, gets its name from the bright white spots that cover its black body. Growing to about six inches in length, it is a good option for medium-sized aquariums.

  • Rubber Lips Pleco:

This fish has a vibrant golden body with black stripes, as well as a spotted head that looks not unlike a crown made out of jewels. Chaetostoma Thomasi grows to about eight inches in length.

  • Bristlenose Pleco:

This fish is scientifically known as Ancistrus Cirrhosus. There is a great deal of sexual dimorphism in this species, with the males having large bushy whiskers and the females have short, stubby whiskers (if they have any at all). These fish can grow to about six inches in length. They are dark brown or grey and have pale spots, and are one of the most affordable types of plecos around. If you purchase a Bristlenose Pleco, be prepared to house it in a tank that is around thirty gallons in size.

  • Sailfin Pleco:

These fish need aquariums of at least 125 gallons in size. These fish have leopard-like patterns and tend to hang out in large groups. They can live up to twenty years in captivity!

Plecostomus Behavior

The plecos is a slow-swimming fish that will prefer to hang out at the bottom of your aquarium, canvasing the substrate for fallen food. They will also attach themselves by their mouths to surfaces such as glass, rocks, and aquarium decorations.
Although they normally swim slowly, they can move quickly if threatened or if you try to pick them up. They will also occasionally dart to the surface of the water to gulp air, a unique feature that only plecos are capable of because they can breathe through their digestive tracts.

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Photo by Ayeung20

Plecos are not aggressive fish, and if they are approached or threatened by a predator, their first instinct is to swim away. However, they have defense mechanisms in a number of ways. They have well-armored bodies and spines, which they can raise to stab an attacking predator. It is not unheard of for fish to threaten a plecos and then become lodged atop the plecos’ spines, detached only with medical intervention.
During the day, plecos will often hide away, out of sight. This can be concerning to a beginning plecos owner, but it’s part of their natural behavior. Because they are nocturnal, they prefer to stay hidden, but can often be coaxed out by providing plenty of floating plants beneath which they can rest.
Despite this solitary, shy behavior, plecos will come out at night to thoroughly clean the aquarium. They are fantastic tank cleaners, preferring to eat algae and other detritus. Some people mistakenly believe that plecos eat fish waste and will even become predators to other fish. This is not the case; while plecos are not carnivores, they will sometimes eat fish that die of other causes. As scavengers, they will take advantage of any food that comes their way.

Plecostomus Tank Requirements

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Photo by José Manuel Reyes

Pay attention to the specific kind of plecos you are purchasing when you are considering how to set up your tank. While most plecos start out around the same size, you need to make sure your aquarium will be large enough to handle your chosen variety as a full grown adult. These fish grow rapidly and will easily outgrow tanks that are too small – while some fish adapt to their tanks and will experience stunted growth as a result of a too-small aquarium, this is not the case with the plecos.
Make sure the species you select can survive and live healthily in the tank you already have. If you are just starting, this is an easy task, as you can adjust the water’s parameters to meet the needs of your plecos. However, if you are adding your plecos to an established aquarium, you need to make sure it can adapt to the existing conditions.
Ironically, although plecos are able to clean up a lot of waste and algae in your tank, they also produce a lot of waste in turn. Therefore, it is essential that you provide good filtration. This helps clear waste and minerals and also helps simulate the plecos’ natural conditions of fast-moving rivers.
It should be noted that a glass tank will be more suitable for a plecos than an acrylic one. Because plecos have dense, sharp spines and mouths that suck with force, it is easy for them to scratch acrylic tanks.
You should provide for plenty of regular lighting to simulate the natural environment. Substrate is not essential, but since plecos like to scavenge, a little bit can be helpful to mimic the act of scavenging through sand or gravel.

Decorating A Plecostomus Tank

Decorations are excellent choices for plecos, as they prefer to have plenty of places to hide. While live plants are not recommended (your plecos will eat these plants voraciously so they will not last long), artificial plants can work well as long as your plecos is not tricked into eating them.
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Providing hiding places like caves, tunnels, and driftwood gives your plecos plenty of places to hide when they need a dark spot throughout the day. Since plecos are so timid, driftwood is a good choice, as it provides shelter as well as a source of food.

Plecostomus Water Requirements

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Photo by José Antonio Cartelle

When you get your plecos home, it is important that you exercise caution in introducing it to its new environment. These easily-startled fish may become alarmed by their new tank mates, and can puncture their bags by extending their spines in fright. Allow your plecos to float in the tank bag for a while, without introducing any new water. After a few moments, you can add some tank water to the bag and then let it acclimate for a while.
Once you open the bag, your plecos will likely dart away to a hiding spot. You might not see them for quite some time, but they will begin to come out at night to feed. Your plecos will quickly grow to a large size when living in your aquarium, which is why you need a large tank.
As a juvenile, your plecos can be kept in a small aquarium, but as it grows, you will need an aquarium of at least 100 gallons in size. If you are raising multiple plecos, it should be even larger to give them room to grow and to live without becoming overcrowded and aggressive toward each other.
Your tank should be about 72 to 86 degrees Fahrenheit, with a pH of 6.5 to 7.5 (soft to medium preferred). While these conditions can vary slightly to suit the needs of your other fish, it is important that you keep the temperature and pH relatively consistent. This will help ensure the health of your plecos.
As mentioned, a good filter is also essential, ideally one that is a hang-on-back style and has a large sponge filter as well. You can also use a power or canister filter to help keep your tank clean. Plecos, like many other aquarium fish, are incredibly sensitive to poor water quality, and can begin to suffer from a lack of appetite and other problems if they are not kept clean and sanitary. Changing out the water in your tank on a regular basis is a good idea, as dirty water can cause holes in your fish’s membranes as well as other water quality issues.
Maintaining a bit of open space at the top of your tank is also essential. You don’t need to cover your tank unless your other fish require it, as plecos aren’t known for being overly curious or for jumping out of tanks. Nor do you need a high level of oxygen. However, maintaining open space at the top of the tank will allow your plecos to come up to the water surface to swallow air. This air gathers in the fish’s bowels, absorbs through the gut walls and provides the fish with the small amounts of oxygen that they need.

What Do Plecostomus Eat?

Plecos are scavengers and will feed heavily on algae, but you do need to supplement their diet with a supply of food, too. Very often, new plecos owners fail to feed their fish not out of neglect, but out of the mistaken notion that the fish do not need to be fed. This can lead to starvation, malnutrition, and eventual death.

Plecostomus fish are omnivores, and are often affectionately referred to as nature’s garbage disposals. This is true to an extent. They will eat everything from plant matter to carrion, but prefer more refined foods when kept in a controlled setting like an aquarium. You can feed your fish anything from algae rounds to earthworms, and they’ll even eat granules, larvae, bloodworms, and small crustaceans. If you are buying dried food, make sure you purchase a high-quality brand that is formulated specifically for plecos.
Plecos can even eat vegetables and fruits from time to time. While these foods don’t need to be a regular part of your plecos’ diet, they can help add fiber and essential vitamins. Consider feeding peeled, finely chopped foods like lettuce, zucchini, spinach, or melon – just make sure you avoid acidic fruits and vegetables, like tomatoes
Feed your plecos at night, when your other fish will be resting and less likely to eat your plecos’ food. Keep in mind that you might not see your plecos come out to eat at first, as it is shy and won’t want an audience while it enjoys its dinner.

Plecostomus Tank Mates

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Photo by Van nguyen huu

Plecos generally have tranquil, easy going personalities. However, mature plecos – particularly those who are at the older end of the spectrum – will sometimes become aggressive with other fish. This can be avoided by raising all of your fish together from a young age, instead of introducing them at varying points in their lives.
Because plecos are relatively shy, they can be housed with almost any other kind of fish. They are commonly partnered with cichlids, bettas, guppies, loaches, mollies, platies, and even gouramis, just to name a few. You do need to be careful housing your plecos with more aggressive species, like angelfish, oscars, and piranhas. These fish are known to nip at plecos’ fins and can cause some serious safety issues.
Because plecos react to threats by extending their spines, they can seriously maim an aggressive fish if they feel attacked. You also need to exercise caution when housing more than one plecos in an aquarium. Mixing species can result in fatal fighting, with the more aggressive species stabbing the more docile ones with their spines as a result of overcrowding.
If you choose to house more than one plecos together – or if you have a tank with more aggressive tank mates – consider utilizing a larger aquarium. Try not to house more than one plecos in a tank that is any smaller than 300 gallons, particularly if you are raising one of the larger species of plecos.

Common Plecostomus Diseases

A healthy plecos will have several key characteristics. When you are purchasing your plecos, make sure you inspect it carefully to be sure you are getting the species you wanted and in a good state of health. A healthy plecos will have clear eyes, a voracious appetite, the ability to attach to the glass, and a tendency to hang out near the bottom of the tank.
Sick plecos will exhibit several telltale signs of illness, such as a pale, muted color or spots of fungus. A sick fish might have frayed fins or cloudy eyes, or exhibit unusual behavior such as daytime feeding or labored breathing.

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Photo by Julie Johnson

One of the most common diseases to afflict plecos, as it is with other aquarium fish, is cloudy eye. This disease is evidence by eyes covered with a white or greyish slime. As the name implies, your fish’s eyes will appear to be cloudy. Your fish might also swim strangely, as its vision is impacted, or have a muted body color. You can easily correct this disease by adjusting the water quality in your tank. Cloudy eye is often caused by poor water quality, so improving the conditions of your tank can help your plecos recover.
Ich is another common aquarium disease. This disease causes white spots to appear all over the fish’s body. It will swim irregularly and may bump itself continually against hard surfaces. If you notice one fish in your tank that may have this disease, you need to separate it from the others immediately. Ich is highly contagious, and can only be eliminated by raising the temperature of your aquarium and using an ich treatment.
If you need to quarantine your plecos, be very careful when removing it from the tank. Their spines easily become tangled in nets, and they will jump and be extremely fast when they feel threatened. The best way to remove your fish is to use a baited fish trap or a container with food inside, which will allow you to trap your fish without it realizing it is being contained.

Breeding And Lifespan Of Plecostomus

When you purchase your plecos, it will likely be very small. As a juvenile, it will likely be only an inch or two, but it will quickly grow in size. Some grow to well over 24 inches! Despite their size, it can be tough to breed plecos without knowing which of your fish are males or females. Some varieties have pronounced differences, but others are more challenging to differentiate.
Plecos are sexual dimorphic and this is particularly noticeable during the breeding season. Some varieties of male plecos have an extended lower lip to help them hold eggs, while other males have cheek spines to use during breeding-related combat. Females may appear to be thicker when viewed from above, while males may also have thicker pectoral fins.

Photo by NRE in SC

That being said, these differences can often be difficult to detect. Bristlenose Plecos are the only type of plecos that can be sexed with relative confidence, as the males will have long, bristly whiskers that are absent on the females. Despite the challenges involved in sexing your plecos, you can breed them in captivity with relative ease.
Plecos tend to breed in caves or other dark, isolated places, with the female laying her eggs on a flat surface. Before breeding, the male will choose a cave that he deems as being ideal for the task. He will then meticulously clean the sides of it and try to draw the female inside. If she is convinced, she will join him, leaving her eggs in the cave.
They are then guarded by the male until they hatch, which takes a few days at most. While the eggs are developing, both the male and female parents may become extremely aggressive toward other members of the tank (including each other).
To breed your plecos, feed both future parents a diet of live or frozen foods, adding a few more calories to their diet every day to boost their health and overall nutrition. Then, move them to a separate tank to spawn. This tank can be set up exactly like the old tank, but it should include extra hiding spots for them to choose from.
When your plecos fry hatch, they will instantly begin to feed. They can eat sinking tablets, disced foods, microworms, or even brine shrimp. Fry can also be fed infusoria for the first few days of life, but should be switched to commercial fry foods after that. Make sure you pay attention to the quantities you are feeding your young plecos, as too much food can quickly contaminate your tank.
In captivity, plecos have far briefer lifespans than those living in the wild. Pet plecos live anywhere between ten and fifteen years, but those that are left in the wild can exceed fifteen years of age. This is likely due to the restrictions placed on their growth and activity when kept in confinement.

Is A Plecostomus Right For You?

If you have a spacious tank that can accommodate the rapidly growing plecos, it could be a good fish for you. While these fish can’t be held solely responsible for cleaning your tank or improving its overall water quality, owning a plecos can be a great way to get rid of some of that accumulated algae, as well as to provide yourself with a fantastic source of entertainment.
While there is some work and a slight learning curve involved in raising plecos, these prehistoric-looking fish are one of the most exciting animals to keep. Precocious and fascinating to watch, plecos are one of nature’s most interesting species. If you want a fish that will provide you with a wonderful fishkeeping experience for many years, owning a plecos might be the right choice for you.

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