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Related Catfish FAQs: Loricariids/more than Plecos, Loricariids 2, Otocinclus for the Aquarium Garden

Other Loricariid Genera: FAQs on: Ancistrus, Baryancistrus, Genera Farlowella, Loricaria, Sturisoma, Rhineloricaria: Twig Plecostomus, Genera Glyptoperichthys, Liposarcus, Pterygoplichthys, Sailfin Giants among the Loricariids, The Zebra Pleco, Hypancistrus zebra, Hypostomus, Peckoltia: Clown Plecostomus, Lasiancistrus, Panaque, Pseudacanthicus, Scobanancistrus, L-number catfish,
Loricariid Identification, Loricariid Behavior, Loricariid Compatibility, Loricariid Selection, Loricariid Systems, Loricariid Feeding, Loricariid Reproduction, Loricariid Disease, Loricariid Disease 2, Catfish: Identification, Behavior, Compatibility, Selection, Systems, Feeding, Disease, Reproduction Algae Eaters

Related Articles: Otocinclus, From Pan-ack-ay to Pan-ack-zee, A Detailed Look at the Bizarre But Beautiful Panaque Catfishes by Neale Monks, Siamese Algae Eaters/CrossocheilusAlgae Control in Freshwater Aquariums by Bob Fenner, Dealing With Algae in Freshwater Aquaria by Neale Monks, (some) Algae (in moderation) Can Be Your Friend, ppt presentation, Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, by Bob Fenner, 

The Giant Plecos of the Genera Glyptoperichthys, Hypostomus, Liposarcus & Pterygoplichthys


 Bob Fenner



The Suckermouth South (and some Central) American family Loricariidae has someone/something for most all freshwater aquariums. Otocinclus and similarly small sized Parotocinclus and Hypoptopoma genera (the family consists of 92), can be kept in ten and more gallon systems in small shoals, with some of the “monsters” we’ll cover here requiring hundreds of gallons of space, not to mention considerable circulation and filtration to keep their systems clean.


                This family of armored catfish easily identified by its “bottom mouth” (the meaning of Pleco-stoma) subterminal-orientation, feeding and locomotory-mouth process (some Plecos live at elevations of more than 3,000 meters, yes, more than 9800 feet, moving up steep rocks, falls by shifting their bodies and mouths). There are some 800 described species with speculations that there may be 1,200-1,500 total.  Plecos and kin can be found in Central (Costa Rica, Panama on down) and throughout South America in nearly every body of freshwater. No marine or brackish species; so no, they don’t like “salt” in their water.

                Common names and scientific abound for these catfishes, and you are encouraged to seek out modern references, like the site PlanetCatfish.com for good image work, and Fishbase.org for meristics and morphometric data per species.


Hypostomus (plecostomus) “the original Pleco”, often touted for smaller, though not suitable for small systems. This erstwhile workhorse is also a “monster Plec”, most topping out at a foot in length, though capable of reaching nearly twice this dimension.  

With more than one hundred described species, the genus Hypostomus is the largest of the family, including what use to be the most commonly imported and cultured aquarium-use "Pleco", Hypostomus plecostomus (Linnaeus 1758) This fish can become attain twenty inches in length. Nowadays Pterygoplichthys pardalis et al. are often sold/labeled as “common Plecs”



Genus Pterygoplichthys:

Two species of rather larger "plecostomus" are bred and reared in large quantities for the aquarium trade, pond-techniques perfected at farms in Florida. Liposarcus anisitsi (Eigenmann & Kennedy 1903) is the Snow King Pleco (formerly of the genus Pterygoplichthys), to seventeen inches in length (thirty inches according to Burgess 1989), and the Leopard Pleco, Glyptoperichthys gibbiceps (Kner 1854) (formerly Pterygoplichthys gibbiceps), at about twenty inches maximum.  <<Ed. Note: Please see images included for selection>>

There are a few species other that make their way into the trade, like Pterygoplichthys multiradiatus, the Orinoco Sailfin Plec and Pterygoplichthys scrophus, one of the Plecs called “Rhino”; though these are rare.


Behavior Notes:

                Giant Plecos, like their more-diminutive brethren are principally nocturnal; eschewing the daylight to move about, seeking food in the darkness of night. Though you may see them out and about during light hours, this is not their preferred time, and may well indicate that either there’s insufficient fodder (to place some food during lights-out for them), something/s amiss w/ water quality or that their tankmates are bothering them.

                One other aspect of behavior that should be noted is these fish’s prodigious production of waste. Likened onto sea cows, they take in a good deal of food volume and… it all ends back up in ones and their system. Hence their need for large tanks, with plenty of water movement, mechanical filtration, and regular (weekly) gravel vacuuming and water changes to maintain decent water quality.


                Like most armoured catfishes, few fishes will bother to tackle their tough sides, but the opposite isn’t always so. The instances of “rogue” behavior, of these fishes “sucking” on the sides of easygoing (e.g. Goldfish) to more rambunctious (large Cichlids) is quite common, and something you should be on the look-out for, possibly calling for the physical removal/separation of parties involved.

                And these Loricariids can be feisty w/ others of their family and at times conspecifics; members of the same species. If there’s room, and in particular if they grow up together, this may not become so much of an issue for the latter; but again, the onus is upon you to assure that all are getting along.

                Oh, and though, strictly speaking these larger Sucker-mouth cats are not plant eaters per se, they will definitely do soft leaved to waxy plants damage even if there’s enough food-greenery around.


                Picking out a good specimen of these fishes is generally straight forward. One item that needs to be stated and reinforced is to NOT buy newly arrived specimens. For a few reasons; the trauma of collection (whether cultured or not), shipping and placement in very different environmental conditions, the mal-effects of starvation ahead of transport, there are times when massive mortalities of these species occur; almost always, soon (w/in a few days) of getting to a dealer’s. Wait a handful of days or pick out yours from stock that has been around a while…. And do assess the individual’s stomach hollow or fullness. You don’t want ones that are too thin, and anyplace else it’s very hard to tell how well-fleshed they are.  Use a net to get the fish to go up on the side panel of the tanks to look at their bellies. Healthy specimens have convex undersides and bulging eyes. Poorly ones have concave undersides and sunken eyes.

                A note re de-selection of these fishes due to their over-growth/size. Quite often, otherwise well-meaning aquarists will end up with giant Plecos that are too big to do well in their limited size settings. Don’t despair, but do be aware, pro-active and humane in getting them to suitable environments. Often, livestock fish stores will trade you a smaller specimen (or two!) for your too-large Pleco. Barring this avenue, often aquarium service companies have need/room for large Plecos. You can usually locate these businesses via the Net or your analog Yellow Pages/Other business directories.  

Large Pleco Systems:

                Three requirements: Big, well-filtered and established, define these fishes worlds. They are or become very large animals in short time w/ good care, and are amazing messy in their food, waste and burrowing habits. Even small individuals should be kept in nothing smaller than 20 gallons, and larger ones require at least 150. Additionally, these Suckermouth cats live in relatively clean, fast moving, mostly riverine conditions. Hence your water movement and mechanical filtration should collectively provide a good ten turnovers of water per hour. And even with all this volume to dilute wastes, gear to move and filter water, considerable (20-25%) water changes per week are strongly encouraged, incorporating thorough gravel-vacuuming in the process.

                Though largely sedentary, the large Plecos need high levels of dissolved oxygen, the more aeration the better. Folks often observe them going to the water/air surface and taking in and exhaling “breaths”. This may be an indication of too low available oxygen or poor conditions (nutrient accumulation especially) period.

                The note re only placing these fishes in well-cycled systems should be revisited. Do NOT place Plecos of any kind in “just new” settings. The water quality is not to their liking, nor the vicissitudes of being exposed to metabolite accumulation ahead of cycling. Additionally, as you can appreciate, there is little for them to feed on when the tank is new.

                Water-quality wise these fishes enjoy a wide-enough tolerance of pH (6-8 is fine), water of medium to moderate hardness, and tropical temperatures (mid 70’s to lower 80’s F.). Regular dechloraminated tap/mains water is good for them in almost all cases.

                Lastly, I’d like to mention that these fishes need to be protected from being burned by heaters. These should be fitted with commercial or do-it-yourself covers to prevent such injuries.



                Many people misunderstand these Plecos dietary needs. One, they are not “cleaner uppers” of fish feces; nor will they live long or well on “left over” foods you’ve presented to your other livestock. In the wild these fishes feed throughout the night on plant and animal materials and sunken/drift-wood. For yours to do well, it needs to be offered these types of foods during lights out hours, and have “bogwood” present in their systems, for décor/hiding and dietary fiber. Plant materials that have employed to good use include types of eggplant, squashes, sweet potato and carrots. These are best par-boiled or moderately microwaved to make them more chewable. There are several excellent “tablet foods” that incorporate meaty and vegetable matter as well… and these can be applied profitably, if you can get them past more active feeders. This usually does not prove to be problematical if you develop and adhere to a program of offering food about the same (lights out) time and place.


                By and large these are tough aquarium species; usually showing signs of parasitic and infectious disease later than other fishes in the same systems. Almost all of these large species are farm-bred/raised; hence the usual troubles with Epistylis, gill flukes et al. of wild-caught specimens are a rarity. Most often, their cause of premature death is from environmental stress… the results of being kept in too small volumes. Secondarily, lack of nutrition is next likely.

                Correcting water quality, system-issues is almost always efficacious to solving health issues, and parasitic ones can be easily cured w/ commercial cures and/or thermal manipulation (e.g. raising temperature for Ich).

                Unless your water is very soft, medications are well-tolerated at full doses, w/ one notable exception: the use of salt. These are not brackish water animals and they will only tolerate about a teaspoon of salt per five gallons. Most freshwater sources already have some salt in them… So, if you’re keeping organisms that prefer salty conditions (e.g. many Molly species) then tankmates other than Plecos are desirable.


                As previously alluded, these Pleco species are captive produced; usually in mud ponds, in which males dig tight-fitting burrows into the sides… attract females and use their bodies to block the entrance while incubating eggs and fry. If you have a system of a few hundred gallons, you might try supplying yours with a sunken pipe with one end open…



                Way too often abused out of lack of knowledge and understanding, the larger species of Plecos need space, deliberate/delivered foods, and a modicum of regular maintenance to do well in captivity. If you think about their natural environments, capacity for growth and ultimate size, it will make sense to select smaller species from the get-go if you don’t have the capacity or intention of providing for their adequate care. There are literally hundreds of other Loricariid species, Ancistrus (Bushynoses), Peckoltias (Clown Plecos), and more that go well with other tropicals, and stay small enough for hobbyist systems. What is more, several of these latter are more attractive than the giant Plecs and more interesting behaviorally.


Bibliography/Further Reading:

Catfishes on the Internet: http://phylogeny.arizona.edu/tree/eukaryotes/animals/chordata/actinopterygii/siluriformes/siluriformes.html

Planet Catfish: http://www.planetcatfish.com/core/index.htm

Baensch, Hans A. & Rudiger Riehl. 1993. Aquarium Atlas, v.2. BAENSCH, Germany. 1212pp.

Brugman, Adriaan J. 1996. Colombia: Fishing for the Royal Plecostomus. OFI Journal Issue 15, May 96.

Burgess, Warren E. 1979. Something new in the subfamily Loricariinae. TFH 7/79.

Burgess, Warren E. 1989. An Atlas of Freshwater and Marine Catfishes: A Preliminary Survey of the Siluriformes. T.F.H. Publications, Inc. NJ. 784pp.

Castro, Alfred D. 1996. Algae al fresco: Exactly which algae eater really likes to chomp down on this stuff? AFM 12/96.

Davis, Chuck. 1979. Choosing suitable catfish. FAMA 6/79.

Dignall, Julian & Shane Linder. 1999. Just say Pleco. TFH 6/99.

Eckstein, Ginny. 1995. Zebra Plecos. So many questions about these little fish. AFM 8/95.

Eckstein, Ginny 2002. Pleco-Mania; are you a sucker for Suckermouth catfish? AFM 3/02

Emmens, C.W. & Herbert R. Axelrod. 1978. Catfishes, 3d ed.. T.F.H. Publications, Inc., NJ. 96pp.

Evers, H.G. 1996. Der hummel-harnischwels O. gibbosus Ribiero, 1908- Ein ausser gewohnlicher wels. TI Magazine 128 Apr. 96, 24-26.

Fenner, Bob & Steve Landino. 1989. Acclimating fishes. FAMA 8/89.

Fenner, Bob. 1994. Guerrilla acclimation methods, or acclimating: My way. FAMA 10/94.

Feuer, Warren. 1995. Rating the Loricariids: You have algae, but will they eat it? Aquarium Fish Magazine 10/95.

Ferraris, Carl. 1988. Basic catfish nutrition: the myth that catfish can live quite nicely on food

ignored by other tankmates is simply not true. AFM 10/88.

Finley, Lee. 1987. On some genera of the catfish family Loricariidae. FAMA 3/87.

Finley, Lee. 1993. Catfish corner: Some notes on feeding Suckermouth catfishes. TFH 8/93.

Finley, Lee. Some Loricariid catfishes. An expert’s assessment of these popular aquarium fish. AFM 12/95.

Finley, Lee. 1996. Vegetables in the diet of catfishes. AFM 9/96.

Finley, Lee. 1997. Catfish Corner: An overview of catfishes bred in the aquarium-part two. TFH 4/97.

Finley, Lee. 1997. Catfish Corner. A "new" Sailfin Loricariid. TFH 5/97.

Finley, Lee. 2000. Catfish Corner: Re the genus Panaque. TFH 2/00.

Finley, Lee. 2000. Big catfishes. All work and a lot of play. AFM 4/00.

Finley, Lee. 2000. Experiences with a blind Loricariid catfish. TFH 5/00.

Frank, Neil & Lisa Sarakontu. 1995. Algae eating cyprinids from Thailand and neighboring

areas (Crossocheilus). The Aquatic Gardener 8(2):3,4/95 and AFM 4/96.

Glass, Spencer. 1998. Twig cats. "Those who’ll play with cats must expect to be scratched". TFH 8/98.

Gosline, William A. 1947. Contributions to the classification of the Loricariid catfishes. Archos. Mus. Nat., Rio de Janeiro, 41:79-144.

Isbrucker, I.J.H. 1980. Classification and catalogue of the mailed Loricariidae. Verslagen en Technicsche Gegevens. No. 22. 181 pp.

Kenney, William R. 1981. Guide and key to living catfish families. FAMA 10/81.

Knaack, Joachim. 1999. A new species of Suckermouth catfish (Hypostomus Lacepede 1803) from the Mato Grosso, Brazil (Pisces, Siluriformes, Loricariidae). TFH 7/99.

Knaack, Joachim. 1999. New Ancistrus species from the Rio Cuiba System, Brazil, (Pisces, Siluriformes, Loricariidae). TFH 8/99.

Kreutzman, Tor. 1997. Breeding Leighton’s Whiptail, Sturiosomatichthys leightoni. FAMA 5/97.

Kreutzman, Tor. 1999. The Bristlenose catfish. FAMA 3/99.

Kutty, Vinny. 1993. Algae eaters. The Aquatic Gardener 6(3):5,6/93.

Linder, R. Shane. 2002. Spawning the Plecos: An Introduction. TFH 8/02.

Loiselle, Paul V. 1989. Bring on the Clowns (Peckoltia). Clown Plecos are excellent aquarium inhabitants, if you follow some simple precautions. AFM 8/89.

Lucanus, Oliver 2006. Let Plecos ply the water in your tank. No one anticipated the popularity and varieties of these bottom-dwellers. AFM 2/06.

Moran, John. Stickfish, all about the Twig Catfishes. AFM 6/95.

Nelson, Joseph S. 1994. Fishes of the World, 3d ed.. John Wiley & Sons, Inc. NY. 600pp.

Nires, Larry. 1998. Plecology. TFH 8/98.

Padovani, Gian. 1988. The Catfish. R/C Modeler Corp., CA. 78pp.

Palicka, Jiri. 1988. Dasyloricaria filamentosa. TFH 10/88.

Poulin, Laura A. 1988. The Farlowella Twig Catfish. FAMA 8/88.

Regan, C. Tate. 1904. A monograph of the fishes of the family Loricariidae. Trans. Zool. Soc. London, Vol. 17:191-351.

Riehl, Rudiger & Hans A. Baensch. 1982 (sixth ed. 1996). Aquarium Atlas, v.1. MERGUS, Germany. 992pp.

Riehl, Rudiger & Hans A. Baensch. 1996. Aquarium Atlas, v.3. MERGUS, Germany. 1104pp.

Sabatino, Charley & Jeff George. 1998. Captive spawning of Ancistrus ranunculus (L-34), A hard to find newcomer. TFH 5/98.

Sands, David D. 1984. Loricariidae: Notes from the score of nature. TFH 10/84.

Sands, David. 1988. A Fishkeeper's Guide to South American Catfishes. Tetra Press, NJ. 117pp.

Schmidt, S. 1996. Prime breeder O. paulinus- an eater of algae with strange tastes. Aquarium (Hilversum) 66(4):100-102.

Seidel, Ingo. 1996. New information on the Zebra Pleco, Hypancistrus zebra. TFH 1/96.

Speice, Paul. 1987. Guppies to groupers: There's a sucker born every minute (Loricariidae). FAMA 2/87.

Staeck, Wolfgang. 1988. Impressive and decorative. Sailfin Catfishes (Pterygoplichthys). Today’s Aquarium-Aquarium Heute 2/88.

Stratton, Richard F. 1999. Lovable monsters: The bristlenosed Plecos. TFH 11/99.

Thomas, Scott B. 1978. Suckermouth catfishes: Nature's algae removers. FAMA 12/78.

Walker, Braz. 1973. Cochliodon, a Sail-fin Suckermouth. TFH 11/73.

Werner, Uwe. 1988. Newly introduced: Hemiancistrus landoni Eigenmann 1922. Today’s Aquarium-Aquarium Heute 1/88.

Wheeler, Stu. 1978. When your catfish calls in sick. FAMA 3/78.


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