Written by Jon Tarn(cup) and Yann Fulliquet


Distinguishing between different varieties of hypancistrus can be amongst the most tedious of jobs for the loricariid enthusiast. Due to their small size, peaceful demeanor, and of course, aesthetic beauty, they are always in demand, and thus, importers continue to scour the South American waterways in search of every newer and ever flashier variants of these animals. It seems that, therefore, this genus was almost destined to become a disorganized, jumbled mess in a classificatory sense—spurred on, in no small way by the confusing L numeral system enacted by Die Aquarien.

This article covers the basics of identifying commonly encountered hypancistrines, which means it excludes the more exotic animals (L-236, 250, 70, lunaorum, 297, and 318), as, assuming you have the ability to obtain one of these rarer animals, chances are you're already well versed in loricariid identification. Plus, I just haven't have enough experience with these fish to give what I feel is an adequate coverage on each of these fish.

The more recent numbers (L-404 and 410) and those which have yet to obtain numbers (hypancistrus sp. "garupa" and others downstream of the Xingu rapids, and a number of completely new animals which have yet to be identified), will also be omitted, due to lack of information.


Hypancistrus inspector-previously L-102.
For some time, the scientific name ascribed to this species was applied to L-201. However, after careful perusing of holotype data, it was understood that this animal fit the description more appropriately. This can be confusing, as the light-on-dark spotted color scheme is quite popular within the genus. As of now, it is the largest known species of hypancistrus, hitting 7”, if not greater. This immense size alienates it from all other congeners. Luckily, it is rather easily identified by coloration and patterning. Firstly, there is a prominent dichotomy between body spot size in the head and the flank regions, the latter being far larger and usually more sparsely dispersed. Furthermore, when viewed in the correct lighting, there are distinctly dark edges along the posterior edges of all major fins—speaking of which, the lower lobe of the caudal is a ways larger than the upper lobe, additionally, the spots on the fin are always placed on the rays of the dorsal and caudal fin. It is also a rather transversely elongated, with the caudal peduncle further back than many other hypancistrus.
Hypancistrus inspector:check for the difference in spot size and the dark edging on the fins. The eye size is also notable.

Hypancistrus inspector:check for the difference in spot size and the dark edging on the fins. The eye size is also notable.




Hypancistrus contradens-formerly hypancistrus sp. “rio venturi”
Another fish commonly mistaken for L-201, this species has only recently been described. Previously imported under the aforementioned number, it was quickly recognized to be of a distinctly separate lineage. The spots appear generally, but not always, whiter in coloration, and are largely more superfluous. However, its most distinctive feature is its large rostrum, with notable ridges—similar to that of L-340, though the head to body ration is not quite as noticeable. It also grows somewhat larger and bulkier than L-201. Another seemingly arbitrary but useful benchmark for identification is that the spot size of the fish is than nostril opening, and are not exclusively encountered on the rays of the fins (as opposed to h. inspector).
Hypancistrus contradens: Large head size and a bulky build.

Hypancistrus contradens: Large head size and a bulky build.




L-201
With copper-orange hued spots peppered loosely about all parts of its body, this is the aquarium staple commonly mistaken to be h. contradens and inspector, and is therefore, still more strongly associated to these names than their rightful owners. Growing to a moderate ~4.5”, it is fairly small amongst the genus, with a stout rostrum and a reasonably compact body build, and while the peduncle is located far back on the tail, the actual fin itself is quite short, as opposed to certain other hypancistrus with more anteriorly located peduncles and flowing finnage.
L-201: Small spot size and a rather blunt caudal fin.

L-201: Small spot size and a rather blunt caudal fin.




L-262
A diminutive, highly attractive species, this fish is dusted with hundreds of small spots-the stark contrast between the spots and the background hue as well as the sheer number of said spots gives the fish a sort of glistening appearance. It does, however, to the untrained eye, bear a striking similarity to L-136 and the Rio Guama L-numerals. It is the smallest fish of the group, however, and is a more compact animal than the aforementioned fishes. It also has a generally dark base coloration relative to the other animals.
L-262: Compare the body shape with the similarly hued L-136, listed below.

L-262: Compare the body shape with the similarly hued L-136, listed below.




L-136
As stated earlier, telling this animal apart from L-262 can be somewhat tricky. However, this is a largely superficial similarity, as the myriad of spots tends to draw the eye away from the actual physical stature of the fish. In reality, L-136 (all three “versions”, as coined by DATZ) is a much more streamlined and often, less vigorously spotted fish. As aforementioned, there are three basic coloration schemes of this fish, which is quite variable--these are all basic polymorphisms of spot size and shape, and the body shape of the animal remains the same. With an elongated head, flatter profile, and streaming fins, L-136 has a far different feel to it than L-262, the latter having a profile more reminiscent of the bulky L-411.
L-136

L-136




Hypancistrus zebra, formerly L-046/098
Dude, seriously?
L-46. If you can't get this one, just stop reading now.

L-46. If you can't get this one, just stop reading now.




L-173
Somewhat trickier to identify, this animal was once encompassed within the h. zebra designation, until in the mid 2000's, DATZ rescinded its initially claim to synonymy. It remains a hot topic of debate as to whether these are the same species, but they do bear a striking resemblance to one another-yet each has its own distinct morphological affectations. If it were up to me, at the very least, I would refer to them as subspecies, but I'm no ichthyologist. Aside from h. zebra, there is very little opportunity for mistaking this animal with any other hypancistrus. With a somewhat darker blue base coloration and a larger, heftier build in respect to h. zebra, it is rightfully placed in its own loricariidae number. Furthermore, it bears a very notably elongated caudal fin and bears polymorphic curvatures in its famed zebra black stripes. There is significant overlap in animals terms of what one might refer to as a zebra and what one would call L-173, however, the above benchmarks are what one should aim for if trying to procure this number.
L-46...compared to the zebra above, it seems to be a distinctly different animal.

L-46...compared to the zebra above, it seems to be a distinctly different animal.




L-316
Of all the hypancistrines, few look as bizzare relative to their congeners as this. The body shape and structure is deviates quite radically from other hypancistrus, with it's long broad head and thickset hindquarters. Males also tend to grow thick odontodes throughout the body, especially along the lower flanks, reminiscent of certain peckoltia, while the interopercular growths tend to be more reserved than that of other hypancistrine males of the L-66 group. The most prominent feature of these animals is their small eye to body ratio. With this in mind, no other hypancistrus comes close to L-316 in terms of eye miniaturization expect L-174, which has a completely different color scheme.
A male L-316. Observe the flat, large head and the eye size.

A male L-316. Observe the flat, large head and the eye size.




L-174
As one of the most visially distinct of the hypancistrines, this animals is mistakable only with one L-400 (differentiatable by smaller eye size and stubbier build). It also stands as one of the smallest animals in the genus, rarely hitting 4", and, despite it's initially creamy white base coloration, can fade, with good care to dark gray. Other pertinent features for identification include, as mentioned, eye size, body structure, and rather significant but unlocalized odontodal growth in males.
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Hypancistrus furunculus, previously L-199
A previously highly sought after fish which, with recent importation prohibitions on Brazilian loricariidae, has been seeing wider distribution as of late. It is very similar to L-270 and debiliterra, however, it tends to grow somewhat bulkier than the either species. When young, it has an enormous eye radius which makes it easily separable from similar animals. As it grows larger, it still maintains a rather large eye size compared to l-270, and has very posteriorly placed eyes, which distinguish it from debiliterra. It also bears thicker vermiculations on its flanks.
H. furunculus-eye placement is especially notable in this picture.

H. furunculus-eye placement is especially notable in this picture.




Hypancistrus debiliterra, previously L-129
Together with h. furunculus and L-270, this fish makes a up a group of similar looking animals that one might easily mistaken for one another. Most strikingly similar are debiliterra and L-270. A rather yellowish-hued fish, the former is a medium sized hypancistrus with a generic body structure. It has a larger head and stouter body compared to the king tiger hypancistrus, but otherwise very similar body proportions to L-270. 270 often has thicker lines in it's body patterning, but morphologically, the main differences between the two are eye size and location (the larger eyes of debiliterra are found facing somewhat more anteriorly on the face), and the length of the caudal fin (more classically elongated in debiliterra).
Hypancistrus debiliterra.

Hypancistrus debiliterra.




L-270
As stated above, this fish is commonly mistaken (provided no catching locality is given) with h. debiliterra. The main points of body structure are shared by the two (somewhat large head, compact features), although, it's eyes are placed very highly on the top of the fish's head. Also, the caudal peduncle region has a bit more girth in L-270 than the reasonably slender tail of h. debiliterra. An confusing point of interest is that the fish designated with the Das Aquarium label "LDA-76", while listed as a synonym of L-270, may be, in fact, to be a different fish. It bears a similar color scheme, although often bearing a more complex and more frequent vermiculate pattern, but tends to grow larger and has a huge head with its eyes positioned even deeper along the back end and higher than those of L-270. However, they are very morphologically similar, and by an ametuerish standpoint, are not different enough to constitute speciation.
L-270.

L-270.




The following fish belonging to what might loosely be termed the king tiger group, are very similar in patterning, and while hints are given as to their general coloration, take note that they can vary greatly from individuals to another. Henceforth, adult size and morphology are definitely the things to look for. However, this can be tricky to for the novice aquarist. That being said...

L-66
The large, vermiculated hypancistrus (i.e., 333, 401, et al) are quite similar in appearance and quite difficult to tell apart. Distinguishing between these animals often requires a discerning eye, and even then, because L numerals do not correspond to a single species (necessarily), there can be a great deal of variety even within a single number. The king tiger, L-66, is no exception. A relatively large fish at around 5-6”, it is a standard bodied hypancistrus with a hefty, but not bulky, body build, and is reasonably elongated when compared with L-333. However, it is not so spindly as L-399; think of it as an intermediate in body proportions. Vermiculations on its pattern are usually rather thin, and more importantly, especially amongst males), connected, to form a “checkered” pattern along portions of the flank—usually, nearer to the belly of the fish, and colors often fade as adults grow into maturity. Again, though, there are likely multiple species encompassed within this number—appearances will vary.
L-66: Note the slight checkered pattern.

L-66: Note the slight checkered pattern.




L-333
Perhaps the most widely variable fish of the genus, L-333 is a name designated seemingly to any such fish that is of the king tiger group that does not have an obvious designation…needless to say, this number is in dire need of cleaning up, but there are a few general guidelines to follow; at least pertaining to the fish first listed in DATZ. This animal is somewhat more compact with larger fins relative to the body than other similarly colored animals. Furthermore, the patterning is less discrete than other vermiculated animals. For example, while the stripes of L-66 generally maintain a relatively uniform anlge along the flank of the fish, thus giving the effect of multiple parallel lines running in a repeated fashion, L-333 markings often stray in a haywire fashion, and may oscillate regularly (forming “squiggles”, if you will). However, markings such as these are a somewhat less reliable way to identify a fish in question, and again, this number still is in dire need of reclassification. It should also be noted that these are very large animals, topping perhaps even L-66 in terms of sheer length and girth.
L-333: a more compact animal-compare to L-66 above.

L-333: a more compact animal-compare to L-66 above.




L-399
For some time, the area around the upper tracts of the Monte Belo region of the Xingu river were fished for L-66. However, more recently, the area has been explored further, and, as a result, a number of new hypancistrus have been coming in, and have henceforth been awarded with L-numbers to match. Granted, these fish are more of a conglomerate of all species found in that particular region, thus, there is some variability within each number. L-399, the first of the two, is a more classically colored hypancistrus, with a light on dark striped pattern and exists in a few like-bodied variants (blame poor classification)—Werner’s photos clearly showcase a number of different fish. It differs from other similar animals by bearing fewer stripes with an undefined pattern. It also has, in some variants, a very distinctly elongated caudal region. The average size of these animals tends to be less than other members of this group--aim for about 4.5", if slightly larger.
L-399

L-399


Another L-399 variant--check for the caudal elongation.

Another L-399 variant--check for the caudal elongation.




L-400
If L-399 seemed confusing, it's local compatriot, L-400 is just as contrived in it's identification. Because of the same region of capture and a number of indiscriminate photos of different fish as unofficial "holotypes", the lines of distinction between L-400 and 399 have been blurred, thus, the one number is usually juxtaposed with the other when IDing an animal of this region. Therefore, to put things simply, if one is unsure of the designation, number wise, of any monte belo caught hypancistrus, it is best to stick with "L-399 or 400", and leave it at that. L-400, by looking at the original DATZ photos, is an attractive, medium sized hypancistrus with a black-on-white color scheme, which immediately sets it apart from most other hypancistrus. It's body shape is slender and elegant, and, compared to other similar animals, bears a noticeably flattened head and a high pre dorsal profile. The tail often bears minor filamentation. The actual patterning of the black lining can be variable, often fragmented and scattered to the point where it might be mistakenly identified as L-174. However, the latter has a very compact body and small eyes that should be sufficient to tell them apart.
L-400.

L-400.


Another L-400. Note the variation in patterning and the body shape of the frontal region.

Another L-400. Note the variation in patterning and the body shape of the frontal region.




L-401
For the last 2 or so odd years, fish imported as L-333, the priciest of the commonly available hypancistrus, began showing up in worldwide markets. In fact, however, it was later discovered that the supposed “new Alenquer” L-333 were in fact from the Rio Curua, a popular residence for several other ornamental loricariids, a number of which are also hypancistrus. The market name of these animals is probably in no small part due to the considerable profits the L-333 namesake reaps, however, in order to be passed off as a different animal, this new fish must have been strikingly similar in appearance, and indeed, it is. The stout, thick body shape of this L number is highly reminiscent of L-333; with it’s large head and body, and the caudal peduncle terminating early in its logintudinal profile. The nuanced differences between the two numbers is limited largely to slight differences in body shape. One of the most prominent features of L-401 is its high, blunt forebody. Whereas L-333 may have a more classically sloping rostrum, L-401 has a more rounded visage with eyes set farther back along its head, not to mention a less posteriorly elongated caudal. Last, while patterning is not often a great way to quantitative L number differences, it should be noted that the vast majority of the patterning in this animal is arranged vertically, relative to the axis of the body, front to back. However, there does seem to be, to no great surprise, a great variety amongst animals imported from this region under the given name, some with lyre like caudals, and more elongated bodies, and more sloped heads. Therefore, it is safe to assume that there are probably multiple species lined up for this number.
L-401. The bluntly sloping forehead and caudal size are apparent.

L-401. The bluntly sloping forehead and caudal size are apparent.




L-411
L-411 was previously commonly seen on the markets listed as L-260. However, by virtue of its larger size and distinct patterning, it was quickly asserted to be a different fish, known later as an animal hailing from the monte dourado region of the Rio Jari. A fairly hefty fish, reaching ~5”, it is distinguished from other similar sized animals, save perhaps L-66, by its complex networked patterning. It is also bulkier, then most comparable hypancistrus, with a thick profile throughout. Its regularly faded coloration is also quite distinct. Still, it is regularly portrayed as L-260, due to very similar striping on the major fins. However, the vermiculations are finer and more concentrated in L-411, and as aforementioned, it does not maintain as consistent of a dark base color as L-260. Very young, less striped individuals still bear a shocking resemblance to L-260, so do bear that in mind-hoever, the faded appearance begins to show at around 3 weeks or so, so there really shouldn't be any confusion.
L-411: note the bulky body features and faded coloration.

L-411: note the bulky body features and faded coloration.