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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, 

/A Diversity of Aquatic Life

The South (and Central) American Suckermouth Catfishes, Family Loricariidae

 Bob Fenner

Scobinancistrus aureatus 


Of the thirty four living families of catfishes, a few stand out as aquarium favorites; the armored cats of the Callichthyidae (e.g. Corydoras, Diadema), the long-whiskered pimelodids, the gorgeous Synodontis of the family Mochokidae, and the "Plecostomus" family of South and Central American sucker mouth catfishes, the Loricariidae. The Loricariids are often called upon to do "double duty" as aquarium specimens; to look nice and be a/the clean up crew removing algae and other waste. The latter role too often doesn't work out as planned.

There are some principal misunderstandings regarding the Loricariids; as basic as which species are which, what water quality they enjoy/will tolerate, providing them adequate to appropriate foods. Many species are in taxonomic limbo and numerous (at least two to three hundred) are yet to be scientifically described. Some are huge, attaining more than two feet in length, and quite aggressive/territorial; fighting back their own or other tankmates. Others, like the genera Otocinclus and Peckoltia are small (a few inches maximum) and retiring.

In "browsing" the electronic bulletin boards regarding freshwater fishes, live plants and aquariums you'll notice a great deal of interest in these "suckers"; and several references to lack of success in keeping many of them. The "formula" for Loricariid success is actually not mysterious nor any secret at all. After handling hundreds of boxes of imports of these fishes, and observing attempts at their commercial production in the Far East, I've come to the this parsimonious conclusion. As is often the case with all livestock husbandry, the principal concerns are merely selection, proper water quality, habitat and feeding.

Classification: Taxonomy, Relation With Other Groups

The Catfishes as a whole are a huge assemblage, some 34 families, 412 genera and 2,405 described species, making up the Order Siluriformes. Of these, the Sucker moth Armored Catfishes, family Loricariidae, collectively termed "plecostomus" or "Plecos" by most hobbyists, are an enormous group themselves. The largest family of catfishes, with about 80 genera and 600 plus known species, systematists subdivide the Loricariids into five subfamilies based on head shielding characters (See Nelson, 1994, Burgess, 1989, FishBase 2000). These fishes are mainly found in swift running streams and rivers but can be found in many other freshwater environments.

You know these fishes; dorso-ventrally (top to bottom) flattened, with underslung sucking mouths surrounding fleshy lips bearing reduced barbels, and spiny body armor ("loricar" means armored). Of special note are Loricariid fish eyes; those omega-shaped pupils dilate and contract in response to varying light. Most advanced fishes eyes have fixed pupils.

A few quick notes here, for comparison's sake, regarding 'other' algae eaters. The most widely sold in the west, the Chinese Algae Eater of Southeast Asia (family Gyrinocheilidae), Gyrinocheilus aymonieri. It only does a passable clean up job when small, becoming a plant (and fish) eater with age/growth. The Siamese Algae Eaters, genus Crossocheilus vie for first place however. We will deal with these minnow-like fishes (family Cyprinidae) in a separate piece. (Images: The Chinese Algae Eater, True and 'False' Siamese Algae Eaters)


Concerning the dangers of "common names", there are too numerous grievous examples of vernacular appellations having nothing to do with scientific/phylogenetic affiliations in our hobby. The Loricariids are not exempt from this confusion. The "Plecos" from the Far East, variously labeled Hong Kong or Borneo Plecostomus are better known as River Loaches, family Balitoridae (formerly Homalopteridae), and are more closely related to true Loaches (family Cobitidae) than catfishes.

Lastly, before launching into the major aquarium genera of Loricariids, a mention of "L" numbers and the group. Some time back, a few of the German hobby magazines initiated an "L number" labeling scheme to identify images of otherwise unidentified species of the family. As they are scientifically described, such numbers are retired'¦ there exists considerable confusion as to identity with this system, as the magazines have been mis-joined in their labeling with other sources. Suffice it to understand that if you're relying on such an identification source as an L-number from a magazine, book, CD-ROM, do identify the reference by name, date.

Some of the More Commonly Offered Loricariid Genera/Species:

Genus Ancistrus, Bristle/Bushy-nosed Plecostomus:


This is perhaps the most useful genus of Loricariids for hobbyists, due to their prodigious algae eating, leaving plants alone, and tolerating harder, alkaline water than other Loricariids. With some 54 described species and many more to come, the Bushy- or Bristle nose Plecostomus are relatively hardy and importantly, stay small (most never exceed six inches in total length). Ancistrus spp. do fine in water of near neutral pH, lower hardness and tropical temperatures. Do eat little algae in the wild or captivity'¦ need supplemental greenery daily. (Images: Ancistrus1 showing head tentacles of a male)


Genus Baryancistrus: Three species. "This genus of Plec is omnivorous rather than an algae eater, and needs catfish pellets and bloodworms alongside the usual vegetable foods. Sorry I can't be 100% certain on these, and I'd direct the owners to the Planet Catfish if they want some real experts to identify these catfish." NealeM.


Baryancistrus niveatus (Castelnau 1855) (tentative ID by NealeM) To about nine inches in length. pH range: 6.5 -- 7.0; dH range: 8 - 10 South America: Tocantins, Xingu, Tapajós and Trombetas River basins. http://www.fishbase.org/Summary/SpeciesSummary .php?id=50006

Baryancistrus demantoides, Werneke, Sabaj, Lujan & Armbruster, 2005 (tentative ID by NealeM) South America: upper Rio Orinoco drainage in Venezuela. http://fishbase.org/Summary/speciesSummary.php?ID=62498&genusname=Baryancistrus&speciesname =demantoides

Help from Neale Monks: The second catfish looks like Baryancistrus sp., something like the "Gold Nugget Plec" of the trade. Another large catfish, more  omnivorous than generic plecs. Sensitive to water quality, doing best in slightly warmer than usual (25-28 C) conditions. Baryancistrus are said to be a bit shy and easily bullied, so choose catfish companions with care.

Genus Farlowella, Twig Plecostomus:

These are about two dozen of narrow-bodied Loricariids from the northern reaches of South America. These fishes and are also distinctive in possessing an elongated bony rostrum on the ends of their head. These fishes are nocturnal algae eaters that are often lost due to a paucity of greens in their diets/environment, and secondarily to poor water quality. Twig Cats require clean water of high-dissolved oxygen content. Note the other similar "twig-like" Loricariids in the genera Sturisoma, Loricaria and Rinoloricaria, (Images: An adult Farlowella in captivity)


Genera Glyptoperichthys, Liposarcus, Pterygoplichthys, Sailfin Giants among the Loricariids:


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. Still these larger aquariums barely begin to measure up to some of the truly big Loricariid species. Some approach three feet in length, not a misprint. (Images: A head shot of a Snow King Pleco, a large size Leopard, and a valid member of the genus Pterygoplichthys).


The Zebra Pleco, Hypancistrus zebra:


A monotypic genus (all to itself), Hypancistrus zebra (Isbrucker & Nijssen 1991), is a real charmer. Though small (about three inches in length, maximum) and not much of a "cleaner upper" of algae it is still a popular Loricariid, and though still collected out of Brazil's Rio Xingu, many specimens are tank-bred and reared for the aquarium trade. (Images: An individual and group of small Zebra Pleco's)


Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.  An unidentified Hypancistrus sp.


Genus Hypostomus, the original "Pleco":


With more than one hundred described species, the genus Hypostomus is the largest of the family. The most commonly imported and cultured aquarium-use "Pleco", Hypostomus plecostomus (Linnaeus 1758) can become attain twenty inches in length. (Image: an aquarium pic of Hypostomus plecostomus).

Verticals (Full/Cover Page Sizes Available)
Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.


Genus Lasiancistrus:


The low body profile has me in mind of (NealeM)


Genus Loricaria: 11 valid species: http://fishbase.org/NomenClature/ValidNameList.cfm?criteria=SYNONYMS.SynGenus+%3D+%27loricaria%27++AND+SYNONYMS.SynSpecies+like+%27%25%25%27+&vtitle=Scientific+Names+where+genus+equals+%3Ci%3ELoricaria%3C%2Fi%3E


Is this a Loricaria, a Sturisoma, a Rhineloricaria, or?

Genus Otocinclus Dwarf Plecostomus:

The genus Otocinclus has at least twenty valid species to date with several more yet to be scientifically described. The classification, or more accurately, identification of these catfishes in the pet-fish industry is often erroneous, but should not worry the hobbyist unduly. All members of the genus are about equally hardy and industrious. To-the-species taxonomy is based on scale counts, teeth and body armor arrangement and relative body measurements. Otocinclus affinis Steindachner 1877, the Golden Otocinclus, is probably the most commonly imported species (out of southeastern Brazil). It is brownish gray overall with a darker lateral body band. Not the hardiest Oto, this species prefers soft, acidic water. (Image: an Otocinclus sp. in captivity)

Just a mention of the closely related genera Parotocinclus and Hypoptopoma though rarely imported, some of these are beautifully eye-catching, and just as suitable as Otocinclus.


Genus Panaque, Royal Plecostomus:


Of the ten described species in this genus, only two are offered in the hobby, and never cheaply. The Royal Plecostomus, Panaque nigrolineatus (Peters 1877) and Blue-eyed Panaque, Panaque suttonorum (formerly P. suttoni) are collected mainly out of Columbia for the aquarium trade, though they are found in Brazil and Ecuador as well. These fishes grow respectively to at least sixteen and nine inches in length in the wild. (Images: A juvenile and adult Royal Pleco in captivity)


Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Excerpted from: Five Almost Perfect Fishes; Great fish for the community aquarium, except for one little thing by Neale Monks   

4                     Royal Plec, Panaque nigrolineatus 

The good:            Classy algae eater that's adaptable and hardy

The bad:              Delicate at first, so needs some TLC to begin with 

Almost everyone with a community tank keeps a Plec of some kind, whether its one of the dwarf Ancistrus or one of the giants, these fish have firmly rooted themselves in the hobby as first-rate scavengers and algae eaters. Nevertheless, many are rather drab, particularly the less expensive but rather hardy species that people setting up their first community tank often end up purchasing. There are of course many very handsome Plecs, but they're often expensive and difficult to find. Falling between these two extremes is the royal Plec, a medium sized Plec that is a bit more expensive than the average catfish but widely sold and easy to find. It is a very good-looking fish, with a body covered in light and dark grey stripes and bright red eyes. A variety of regional varieties and subspecies are sold under the royal Plec moniker, often referred to by catalogue numbers known as 'L-numbers', for example a royal Plec with a greenish hue is known as the olive royal Plec, L027b. 

Regardless of the actual name or number of the fish you have, all royal Plecs can be kept be in the same basic way. Like other Plecs, they are primarily nocturnal herbivores and particularly relish green algae and its substitutes (such as algae wafers, blanched lettuce, and strips of courgette). One peculiar dietary requirement is wood: they do appear to eat this stuff and fare badly without it, so some bogwood should always be placed in a tank containing royal Plecs. They are retiring animals and do best if given a cave or hiding place of some sort, and can be territorial if forced to compete for space with other catfish; but they are otherwise very peaceful and will not harm other any other fish, even very small ones like livebearer fry. As far as water conditions go, they are relatively tolerant of pH and hardness (my specimen is over ten years old and has always been kept in the hard, alkaline water typical of South East England). What royal Plecs do need is a decent current and plenty of oxygen as these are fish of fast flowing streams rather than swamps or ditches. In this regard they are much less adaptable than, say, common Plecs such as Hypostomus punctatus that are able to breathe air if they need to. 

Although a big if slow growing fish -- typically reaching 15 to 20 cm in home aquaria -- this isn't the main problem with the royal Plec. In fact, this moderate size makes them good companions for medium to large fish such as Gouramis, climbing perch, angelfish, and spiny eels. No, the thing that prospective owners need to brace themselves for is the rather tricky phase immediately after buying the fish and bringing it home. Like a lot of the wild-caught Plecs, these fish don't travel well, and by the time they arrive in your local tropical fish store will likely be half-starved and severely stressed. Many specimens fail to survive because their owners do not give them optimal water conditions and all the food they need to put some weight back on. There is in fact a very good argument for placing these fish into a quarantine tank for the first few weeks so that the aquarist can watch the fish carefully and make sure that it is eating well. Obviously slicing up some vegetables is much less taxing that trying to wean a predatory fish onto dead food, but still, this is something that the aquarist needs to tackle diligently if his new fish is going to do well. 

It is just as important to make sure that you buy a fish that isn't so thin that it isn't going to make it whatever you do: avoid specimens with sunken eyes and hollow bellies. The best retailers make sure their fish are feeding well before they sell them, and given that these fish are pricey to begin with, it's well worth your while tracking down a retailer with a good reputation for handling South American catfish generally.

Genus Peckoltia, Clown Plecostomus:

These small (3-5 inches) Loricariids are not as hardy in shipping or acclimation to captive conditions, but are sturdy enough if/when brought in well, and once they settle in'¦ and they almost always leave live plants alone. Also of note, though they are often pictured and housed together in captivity, Peckoltia species are best kept either one to a tank (even if a large system), or pairs. They're easygoing with other bottom dwellers but very aggressive toward conspecifics. (Images: three Peckoltia spp.)

Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.


Genus Pseudacanthicus, six species:


Pseudacanthicus sp. According to Neale Monks: A large, territorial *carnivorous* rather than herbivorous Plec. Eats bloodworms, chopped seafood, etc. as well as algae wafers and other Plec-type foods. In the trade these are called things like "cactus Plecs" and "scarlet Plecs"

Incorrect ID, Loricariid, WWM  7/12/09
Hi guys.
You have an interesting site and I've enjoyed looking through the Fresh Water Desktop Archives.
Just thought you'd like to know i believe there is an error in Archive 8.
http://www.wetwebmedia.com/FWSubWebIndex/FWDailyPIX/FWDP Arch 1-12/fwpotdarch8.htm
The Photograph at the bottom is listed as Pseudacanthicus sp.
But is in fact Pseudorinelepsis genibarbis commonly called "Orange Cheek Pleco" more information on this species can be found here:
<Ah, good catch! That's my fault I suspect; Bob often sends these freshwater fish photos to me, and I do my best to name them, though in this case, apparently incorrectly. Apparently, a good indication of
Pseudorinelepsis and its allies when compared to most other Loricariids, including Pseudacanthicus spp, is the plain circular iris as opposed to the omega-shaped iris usually associated with Loricariids. That indeed matches the fish in Bob's photo, so your identification certainly looks good. So I've learned something today!>
Keep up the good work
Pleco Fanatic
<Thanks for writing in! Cheers, Neale.>

Genus Pterygoplichthys:

Pterygoplichthys gibbiceps (Kner 1834), the Leopard Pleco. To 50 cm. pH range: 6.0 -- 8.0; dH range: 5 - 19, Tropical, South America: Middle and upper Amazon and Orinoco basins: http://fishbase.org/Summary/SpeciesSummary.php?id=12219
Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Genus Scobanancistrus:

Scobinancistrus aureatus Burgess 1994. To 25 cm. South America: Xingu River basin. http://fishbase.org/Summary/species Summary.php?ID=57543&genusname=


Genus Sturisoma, Royal Whiptail Plecostomus:


Hearty feeders on worms, insect larvae, crustaceans like Daphnia and Brine Shrimp and prepared foods. Some species at times sold as "Royal Farlowellas", though the genus Sturisoma's larger heads and distinctive dorsals easily distinguish them and worked tail fins. And though they look fragile, this genus' members make sturdy aquarium additions. (Image: a tank bred juvenile and adult Sturisoma in captivity).

Sturisoma sp. possibly. A Loricariid in any case. Interzoo 2010.

Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Excerpted From: Moving on'¦ So you've kept a community tank going for a while. What's next? by Neale Monks L-number catfish 


Armoured catfish of the family Loricariidae are literally being described faster than scientists can describe and name them, and so a shorthand system of identifying these catfish has come into use, the L-numbers, where 'L' stands for 'Loricariidae'. Not all the armoured catfish have L-numbers; species that have been recognised for decades, like the common Plec Hypostomus plecostomus, don't have L-numbers, and neither do catfish belonging to other families, such as Corydoras

Even after a catfish receives its proper scientific name, many aquarists continue to refer to them by their L-number. So the zebra Plec, Hypancistrus zebra, is L046, and the Sailfin Plec, Glyptoperichthys gibbiceps, is L083. But L-numbers are used most commonly for the species that are new to the hobby. The gold nugget Plec, Baryancistrus sp., for example, is L018, and the 'watermelon' and 'olive' varieties of the royal Plec, Panaque nigrolineatus, which may or may not be distinct species, are L027a and L027b respectively. There is a good deal of variation among the L-number catfish, in particular with regard to size, with some being dwarfs comparable to the popular Ancistrus catfish and others being giants that can exceed lengths of 60 cm (24 inches). 

L-number catfish can be a great addition to the community tank because for the most part they share many of the characteristics of the more familiar Plecs. They are generally peaceful omnivores that do not pose any kind of threat to other fish in the tank. Some are notably more demanding in terms of water quality, but others are robust and hardy. Almost all Loricariid catfish are territorial, which usually translates to keeping one to a tank, though smaller species can be kept in groups provided the aquarium is large enough, and breeding them is a distinct possibility. 

Just as with the more common varieties of Plec and whiptail catfish, these fish are to a large degree herbivorous, and green algae, blanched lettuce, peas, and slices of zucchini being considered good staple foods. In addition, many readily take small meaty foods such as shrimps and bloodworms, as well as regular catfish pellets. Some species also eat wood, in which case a piece of bogwood should be placed in the aquarium for them to graze on. 

Buying an L-number catfish isn't difficult, with many aquarium stores regularly keeping the more attractive varieties in stock all year round. Many are inexpensive, but some can cost more than marines, so in part your choice will be dictated by budgetary considerations. One thing to look out for is how well these fish in the store are eating: with many species, if they lose a certain amount of body mass, they never seem to recover and eventually die. Only buy specimens that look plump and healthy.


Natural and Introduced Range

The Loricariids are entirely freshwater and of the New World, Panama to most of South America, in waters of low elevation to more than 3,000 meters, still to swift flowing.


Watch those nets! Plecos should be ideally caught by coral-ing into a corner and picked up either by hand or in a specimen container. They often have bristles on their fins and often as parts of their gills... that get stuck but good... Necessitating the cutting of netting material (don't pull on the fish!).


Selection: General to Specific: Several Criteria to Consider

Pick out initially healthy stock; this is a crucial and difficult task, and no, I have no crystal ball. The majority of Suckermouth Catfishes are wild caught and imported. Some shipments of are almost 100% DOA, others the opposite. Sometimes "bad" (more than 50% lost at the get go) imports suffer very little consequent loss, whereas others are all dead for no apparent reason within a few days. A few generalizations are of service: 

1) Look closely at the whole batch; every individual in the place. How do they seem? Are they full bodied; that is, not skinny? Look at their abdominal regions and their eyes. These should not be sunken in. Are the fins intact? Not frayed or whitish? All breathing? Are they alive at least? Good, go to 2).

2) Look for good color, olive brown, black and white where it should be for the species. See any with grayish white, or bloody marks, especially at the parried fin origins and belly area? If their skin is damaged, leave them all.

3) "How many do you want?" Pick out the active individuals, those cleaning up, that are moving around. Omit the skulking, immotile ones having "private parties" in tank corners.

4) How long have they been there? If they're going to die, they generally do so within a few days... from "ammonia" (or other metabolite poisoning), low oxygen, lack of feeding, poor handling in general. Wait for them to "plump up" and stabilize.

X) For you wholesalers, retailers who are receiving and holding these animals for a while (as opposed to transhippers, break-packers/jobbers): A) Do utilize acidified water and Methylene blue (for oxygen carrying ability and anti-microbial effect) in acclimation (Fenner gratuitous self-citations below). B) And make sure they're provided with some driftwood and other purposeful food. The best outfits I've seen keep some microwaved/blanched zucchini, nutritious food blocks, and defrosted frozen bloodworms in their system at all times. C) De-worm them en-masse with medicine (hobbyists can use Tetra's medicated food for parasites) applied to the food, before sending them on.


Environmental: Conditions



If you'll take the time to seek out and acclimate healthy Loricariids and do nothing more than provide them with an appropriate habitat, dark spaces, perhaps some live plants, and clean moving water of high oxygen tension, you will find them to be extremely hardy.

As a corollary, don't be too fastidious about scrubbing the system sterile; instead just clean the front or viewing panel(s) leaving some algal growth, mulm and bacterial populations.

Most species are nocturnal in the wild, with many of these becoming crepuscular to diurnal in captivity. Still others are not as naturally nocturnal as their sucker mouth brethren, but do appreciate cover to get out of the light and into hiding. Ideally this would be a combination of plantings, submerged wood, and other decor.


Many species (e.g. the more coastal Ancistrinines) display a wide tolerance to given standard aquarium-utilized parameters, living well in soft to hard (zip to 400+ ppm total hardness), acidic to alkaline (5.5 to 8.0) waters. Other species display less tolerance. You will need to investigate the ones you are interested in, though most do fine with less hard (<100ppm total), near neutral pH water (7.0).

They do display an objection to high concentrations of organic metabolites however. You should have no detectable ammonia, nitrite, and low nitrate (much less than 10 ppm) levels. The steps to maintaining these criteria are simple; under crowd, underfeed, properly filter, and do regular maintenance (in particular water changes) regularly. Poor water quality very often manifests itself in death due to apparent bacterial infection.

Temperature range is wide enough, 72-82 F. (21-27 C.) for most species. If summer temperatures peg out much higher, cut back on your lighting and do definitely increase/add aeration.


Should be vigorous and complete; move all the water around and through the mechanical, biological plus possibly chemical filter media a good twice plus per hour. As long as it does not disturb your plants, you can't have too much water turbulence.

Additionally, weekly water changes of 25% are recommended to keep metabolites low and the system "dynamically stable" (love those oxymoron's!).


Though these are technically armored cats, they should be handled gingerly, as little as possible, and only then with fine meshed nets or guided into specimen containers without. Avoid touching them by hand, wiping off their protective mucus and possibly getting spined by their spiny dorsal and pectoral fin spines. Instead, if you utilize them, invert the net and cats into the intended system's water and let them extricate themselves. Commercial operations do well to fashion shallow draft, rectangular nets utilizing fiberglass screen door netting for these and other similarly spiny livestock.

Behavior: Territoriality

Some Loricariids are decidedly agonistic toward conspecifics, the clown "Plecos" (Peckoltia), and Royal types (Panaque) come to mind. Such is not the case with Otocinclus for instance; they get along with their own, other members of the genus, in fact with most everybody. There are citations that call attention to "riding" and parasitic sucking on fish tankmates by Loricariids, but rarely are these recorded as being ultimately deleterious to the host. More likely this behavior is a manifestation of food deprivation, imminent death of the fish being eaten, and a sign that you need to be supplementing their diet.


Due their intolerance of cycling metabolites and fondness for algae these fishes are best placed in well-established systems; particularly ones where there are live plants that have become firmly settled and are growing.

Most species are best-utilized one to a tank, unless you have plans for spawning them or a very large system. But there are exceptions here as well. Otocinclus should be purchased in a group (one or two per ten gallons of system is about right functionally), being social animals, and batch-processed via a dip and quarantine procedure (Fenner, 1989,94).

Predator/Prey Relations

Most all small to medium size and aggressive fishes get along with Loricariids. Larger, more aggressive tankmates and generally agonistic species might be tempted to try picking on them; for their tanks, try the larger Loricariids.

Reproduction, Sexual Differentiation:

Sexing many Loricariids is not difficult, but takes a trained eye. In some, definitive gill cover spines and pointed genital papilla of males can be made out; in most species sexually mature males tend to be more broad in the head. Looking to the females, they are decidedly broader and rounder in appearance. When fecund and sucking onto the side of their tank, eggs can be seen with a flashlight through their vent area.

Due to mixed species shipments, the wannabe breeder is encouraged to purchase and stock a given species in as large a grouping and system as practical, and provide propitious circumstances (food, habitat, water quality) for nature to take its course.

Most species of Loricariids are recorded as male-nest building and parented; females only being tolerated if egg bearing, then driven out once they've laid their eggs. Otocinclus are listed by some authors as "egg scatterers" contrasting with most of the other egg-laying Loricariid genera. Young of the family hatch out in 4-20 days... with many folks listing baby brine and spinach as first foods. For much more on spawning accounts see the references below, particularly Burgess (1989). 

Feeding/Foods/Nutrition: Types, Frequency, Amount, and Wastes

Inadequate feeding/nutrition is only second to selecting decent specimens as a source of mortality with these fishes. Three key points again; do not place Loricariids in new, or overly cleaned systems, they will perish from lack of food. Secondly, you must expressly provide foodstuffs for these suckers, (e.g. sinking pellets, greens like cooked spinach, Nori, peas) especially if keeping them in an unplanted or under-planted setting. And lastly, the "wood trick", that is, supplying your Suckermouth Catfishes with some submerged wood as a needed dietary adjunct. 

Disease: Infectious, Parasitic, Nutritional, Genetic, And Social

Though they have sturdy body scutes the South American sucker mouth catfishes are barely armored against poor water quality. This shows up in their ready susceptibility to "organic pollution". For a dearth of water changes, otherwise adequate filtration, they often, too often die from bacterial-population-explosion "disease". Maintain high water quality.

On import, internal worms, mainly of the gastrointestinal tract and gill flukes can be lethal. Don't trust your livestock source to have done the job on these. During quarantine, feed your new Loricariids anti-parasitic food for a good week. Tetra "¢ makes an anti-parasite food of use here, or you can devise your own using Metronidazole/flagyl. Captive-bred specimens are of course, almost always gill and internal worm free.

The too-common infestations of ich can be quickly resolved with malachite with or without formaldehyde preparations. Be wary of utilizing too much salt, metal (copper) or insecticide (DTHP, Masoten, Dylox, Neguvon) medications on these catfishes; they succumb to these treatments more readily than the apparent cause you're treating.


The Suckermouth Catfishes are amongst the "world's most useful algae eaters" for planted and non-planted aquariums. They are largely peaceful, unobtrusive, and industrious, readily available and interesting behaviorally. Beyond these considerations the sheer diversity of this family of cats offers a lifetime of opportunities for engaging work in breeding, experimentation and fun.

If you intend to put them to good use, just keep in mind the four cardinal points offered here. Pick out healthy stock, keep water quality high and constant, provide a suitable habitat, and suitable food including some submerged wood.

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.

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 Magazin 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 & Liisa 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.

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

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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