Last Updated: 2/14/20
Common Plecostomus Species- telling species apart
Plecostomus Behavior - behavior, size
Plecos Sucking on Other Fish
Pleco to Pleco Aggression
Setup and Water Preferences
For information on algae-eating animals, check out the algae-eating animals comparison table which includes some information on other species of plecostomus as well as lots of other animals.
Common name: Common plecostomus, suckermouth catfish, algae eater (also
used for other unrelated species of fish), pleco, pl*co (the internet superstition is that if you spell
pleco out, the plecostomus will die), plec (in the UK), sailfin pleco (just for Liposarcus' and
Scientific/Latin name: Pterygoplichthys pardalis (formerly Liposarcus pardalis and Pterygoplichthys multiradiatus); other common and similar species include Liposarcus multiradiatus, Hypostomus punctatus (formerly Hypostomus plecostomus), Liposarcus anisitsi (more gray in color, the snow king pleco), and other Hypostomus, Pterygoplichthys, and Liposarcus
Maximum length: 1 to 2 feet (specifically 16 to 20 inches for Liposarcus species)
Colors: Brown, black, mottled.
Temperature preference: 68 to 82 degrees
pH preference: 6 to 7.5
Hardness preference: Soft
Salinity preference: Low
Compatibility: Good with small fish; may suck on goldfish, discus, and other large, flat-bodied fish; devours plants; will eat dead fish
Life span: Unknown, maybe 10-30 years (Steve told me on 12/1/04 that he has a 14-year-old and a 20-year-old pleco)
Ease of keeping: Moderate
Ease of breeding: Difficult
Common Plecostomus Species
The "common" plecostomus are those that are sold as "algae eaters." They are all mostly non- descript (although some are spotted) and grow to one or two feet long. They are inexpensive. A lot of the information on the pleco pages also does pertain to the "fancy" plecostomus which tend to cost more and can range from only a few inches long to over two feet as adults. "Common" plecos and "fancy" plecos are not an official classification but merely one that I am using.
Species and telling plecostomus species apart:
Hypostomus punctatus, or Hypostomus plecostomus as it was known for so long, is a suckermouth catfish with patterned brown skin. So is Liposarcus pardalis but since it is not in most fish atlas', I did not know that I did not have a Hypostomus until an expert saw photos of Plecy. The "expert" said I had L. multiradiatus which is in the first Baensch atlas as Pterygophlichthys multiradiatus. The photo shows a yellowish fish that does not look like my fish. A catfish expert says that they can change color and because my pleco was not expensive, it must be a L. multiradiatus. I was not so sure. Another person contacted me saying I had a L. pardalis. The expert at Planet Catfish agreed. Yet another person wrote in my guestbook that they swear I have a Glyptoperichthys or Liposarcus scrophus. I looked at the photos at Planet Catfish though and the photos look absolutely nothing like Plecy. Do any other experts want to tell me which species they think I have?
Update 2/14/20: Plecy died today at 26 years old. The identification of his species as Liposarcus pardalis at the time was correct. The photos on Planet Catfish now almost all look exactly like Plecy did. The scientific name for Plecy's species has since been changed again to Pterygoplichthys pardalis.
Needless to say, it is very difficult to tell apart most of the common plecostomus of which there are dozens of species.
Liposarcus (sailfin pleco) species:
From what I have gathered, there are three commonly found species of Liposarcus
which may have gone by the genus Pterygophlichthys in the past or even now.
Here they are:
One person experienced with plecos says that the best way to tell Liposarcus multiradiatus from Liposarcus anisitsi is that the Liposarcus multiradiatus has a circle-like pattern on its belly while Liposarcus anisitsi has lines. Otherwise, the two species may look the same since plecos are so prone to color variations and changing color to suit their substrate and mood. The snow king pleco not only occurs as the more white individuals but also ones that look like regular common plecos as well. So, I think most pleco owners really do not know for sure which species they have if they have a "common" pleco! Even experts do not always agree.
Telling pleco genuses apart:
Pleco species can be told apart by the number of rays in the dorsal (back) fin.
Hypostomus have 8 or 9; Liposarcus, Pterygoplichthys,
and Glyptogolipthychs have more than 10 (usually 12 or 13); and
Cochliodons have 10. My pleco seems to have 12 rays (he will not sit still!). (I
verified the 12 rays in November of 2004 as he sat still and again on 1/14/07.) It is
easy to tell the fancy plecos (bristlenose, Queen Arabesque, snow balls, gold nuggets, mangos, zebras, clowns,
etc.) apart from the common plecostomus due to different patterns and colors and high prices.
There are also plecos with different body shapes and features like the bristlenose plecos.
For more information on the species of plecostomus, visit the pleco fact file.
Plecostomus behavior and size:
Plecos patterns change with the background and their mood. The common plecostomus or pleco is sold in large numbers. References to pleco are specifically referring to the common pleco species (Hypostomus plecostomus, Liposarcus pardalis, Liposarcus multiradiatus, etc.) and not necessarily other species. The pleco should not be sold with so little thought to unsuspecting customers (yes, I was one in 1995!!). First, plecostomus grow big, big, big!! The little two inch ones that they sell at the pet stores grow typically to nearly a foot if well cared for. Do not buy one, intending to keep it forever, unless you have a tank of at least 50 gallons. Liposarcus/Pterygoplichthys species grow to 16 to 20 inches. Mine was 14 inches as of December 2008 and was at 15 inches on the day of his death on 2/14/20.
Plecostomus are nocturnal. They feed on mostly plant material at night. During the day, their unusual omega iris blocks a lot of the light out of their eyes. The iris opens at night. Plecos can also wink using an eye membrane. Plecos need to have a safe and dark place in which to sleep during the day in order to feel comfortable. Plecos will sometimes come out during the day especially when other fish are fed.
Plecos Sucking on Other Fish
Most plecos eat plant material including algae. But, they do need some protein. I dropped in some sinking shrimp pellets for that. If the plecos are hungry and/or just feel like it, they may try to eat fish. I have gotten very rare reports of them actually eating healthy fish but, I think, in most cases, they were actually seeing the plecos eat fish that had died from other causes. Most fish will eat dead fish. When a pleco has a large surface on which to suck, it can attach to a fat- bodied fish and rasp away some of the slime coat or even the scales and flesh. This most often happens when the plecos are small, and the other fish are large. When a fish is sick, that makes it more likely that the pleco will suck on it and not be tossed off. Sucking is not likely to occur with huge plecos and tiny fish. I kept my large pleco with both tiny tropical fish and smaller goldfish without problems. After being sucked on, fish will often develop a bacterial and/or fungal infection which can eventually result in death. Just because you have a pleco with goldfish, koi, discus, or other such fish, and nothing has happened yet, does not mean there will not be a problem in the future. I had my pleco with larger goldfish when he was small for over a year before he sucked on them.
Sometimes, plecos just love to suck on ailing goldfish, discus, and other fat bodied fish. Avoid adding them together in the first place if possible. There is one pet store near me that has about 20 tanks of fancy goldfish. Every tank has a small plecostomus and, at any time, half of them are sucking on a goldfish. The employees apparently believe that any damage overshadows their algae cleaning abilities (in other words, they are too lazy to clean off the algae and do not care about the goldfish). My pleco probably killed the two rosy barbs with him around 1997 even though he was 9 inches long, and they were only about 1.5 inches long. Before that he harmed my goldfish. For more about my pleco with goldfish, visit my goldfish care page.
Pleco to Pleco Aggression
Large common plecostomus (this does not hold for many other species of pleco) are territorial and will usually not tolerate another large plecostomus in their tank. This may only be a same-species phenomena with two plecos of dissimilar species but similar sizes getting along without incident. Some of the more exotic species, such as the interesting bristlenose plecostomus, often get along with their own species at all sizes. I have never had more than one pleco at the same time in the same tank (except in a bunch of dreams). Some aquarists report severe aggression; others say they get along fine. One person even said they had two plecos who were unhappy if separated. It most likely depends on species, size, and individual temperaments. Fish are individuals!
This said, plecostomus are great and interesting fish. In a large tank with small fish, nothing can beat them for algae cleaning capability. There are many other species of plecostomus more suitable for smaller tanks. Some are relatively inexpensive like the bristlenose pleco and clown pleco and some command higher prices like the gorgeous zebra, scarlet, and mango plecos. These often smaller other species of pleco are also often much less damaging to plants. The zebra pleco for example is much more carnivorous and eats little algae or plants. The bristlenose pleco is a good algae eater that usually leaves plants alone (see my bristlenose pleco page. It grows to a moderate length and can breed in captivity. Plecos can live a dozen years or more. Mine lived to 26 years of age (yes, really!). One of my books says that Hypostomus punctatus (and presumably Liposarcus species) is a "harmless loner." Small fish may agree but many of my and other people's goldfish and plants would beg to differ!
Setup and Water Preferences
Common plecostomus need big tanks as adults. Or they can grow with your hobby. Every time I got a larger tank, good ole Plecy moved in it. Adults need tanks with a minimum volume of 50-100 gallons.
Plecos come from the Amazon in South America. They thus prefer water that is slightly acidic or neutral with a pH of 6 to 7.5. The water there is normally pretty soft but plecos can adapt to water of moderate hardness. Plecos not only suck algae with their mouth but use it to hang on to rocks in swift moving waters. So, they do enjoy some current in part of their tank with moving water. Because they come from moving water, plecos need a lot of aeration in their tank to be sure they get enough oxygen (although they can gulp atmospheric oxygen too).
Plecos are remarkably tolerant of a wide range of temperatures. They are most comfortable around 70 to 75 degrees F but can adapt to temperatures from 60 to 90 degrees F. Some individuals of some species may tolerate water below 60 degrees F. How low is up for debate but at least down to 50 degrees F. Aside from a few stories of super plecos surviving in ponds with ice on them, it is a very good bet that a pleco will die if left in water below 50 degrees F.
My plecostomus survived a 42 hour power outage at about 55 degrees F for most of that time. I had battery air pumps. Not only did Plecy survive, but he was looking for food most of that time and thought night time was all the time!
Plecos make a lot of feces in long strands. That is another reason that a tank with a pleco should receive frequent partial water changes. While plecos do not like a lot of salt, adding just a tablespoon per 5 gallons is safe for them and has its benefits (see my salt page for more information).
In a pleco tank, there should be a place to hide during the day. That is easy enough for the little plecos but harder for the big ones. You can try PVC pipe, clay pots, or various fake rock enclosures. The one my big pleco used (2008) was a faux rock turtle ramp. I put two of them together to make a tunnel, and later I had three of them (he spanned the entire length inside!). He slept in there all day. In addition to a place to hide, a pleco tank should have some driftwood on which the pleco can rasp. It aids pleco digestion and gives him something to do. For how to treat driftwood, see this section.
The addition of live plants will certainly make a common pleco happy. It may not make you as happy. Most larger common plecos will devour plants and generally make a big mess.
Continue to the plecostomus care page two.
Back to the main plecostomus page.
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