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Keeping Up With The L Numbers
18 December 2016
Aquarists are often surprised that many of the fishes offered for sale as so new to science that they do not even have a Latin name yet. The South American catfishes of the Loricariidae family are a good example of this. As fish collectors search ever more remote locations, literally hundreds of new species have been discovered.
To solve the problem of what to call these fishes, in 1988 the German aquarium magazine Die Aquarien und Terrarienzeitschrift began using a classfication system eventually known as the L-number system. Each new species was photographed, carefully described, and then given a number. The prefix L stands for Loricariidae, and then the next three numbers are applied sequentially. Eventually the L-number catfish receives a proper Latin name, and the L-number is retired, never to be used again. L001 is now known as Glyptoperichthys joselimaianus, L015 as Peckoltia vittata, and so on.
L-number catfish are popular not just because they are new and unusual, but because many of them make exceptionally interesting and attractive aquarium fish. While loricariid catfish do tend to be rather similar in some respects, there is a surprising degree of variation among them. Some are no bigger than Corydoras, while others top 60 cm in length and obviously demand a big aquarium with excellent filtration. Though often considered to be simple scavengers and algae-eaters, many are quite specialised in their diet. Some eat meaty foods such as dead fish or insect larvae, while others can consume and digest wood. Most appreciate leafy and root vegetable foods, such as spinach, lettuce, carrot, courgette, and sweet potato. These should be supplemented with commercial plec foods. Though many species are harmless loners, some prefer the company of their own kind, while others can be distinctly hostile even towards other species. So researching a fish before buying it is absolutely essential. For any aquarist interested in L-number catfish, a resource like Aqualog Extra - The Latest L Numbers is a very worthwhile purchase, given that L-number catfish rarely appear in the more mainstream aquarium books.
Incidentally, you might also come across loricariid catfish numbered with an LDA prefix instead of just L; these belong to a similar listing to the L-number system, this time devised by another German magazine, Das Aquarium.
Buying and settling in L-number catfish
Broadly speaking, L-number catfish are hardy and present the aquarist with few major problems. The main issue is that the fish should be in good physical condition before purchase. Starved fish in particular often do not recover, however well the aquarist cares for them. For this reason, it is always a good idea to pick fish that are feeding well. Look for fish with fully bellies and bright eyes; fish with hollow bellies and sunken eyes are best avoided.
Once you have your fish home, find out about its correct diet and act accordingly. Commercially produce plec pellets and algae wafers are a good staple. Some aquarists like to quarantine L-number catfish carefully before putting them into a community tank; this gives the aquarist a chance to look over the health of the fish and if necessary deal with parasites or superficial damage to the fins and scales. It is also good to let the fish get "fattened up" before it has to compete with other species in a community tank.
Finally, check on the preferred water conditions for your new catfish. While loricariids generally are adaptable, and many will do well in hard, alkaline water, some need soft and acidic water to do well. A few come from fast water habitats, and will require additional aeration and water movement.
A few of L-numbers available now
L006 has been formally named Peckoltia oligospila but it is still known by its L-number designation. One of the smaller loricariids at about 10 cm long when fully grown, this is an excellent resident for a clean, well maintained community aquarium. As is typical for Peckoltia, this species is an indifferent algae-eater and prefers meaty foods, in particular insect larvae. Soft plants may also be eaten. Territorial, but provided each fish is given adequate tank space they can be kept in groups.
L014, now known as Scobinancistrus aureatus, is one of the more spectacular loricariids and always popular with aquarists. Juveniles have a greenish body covered with small white spots, and the fins are a rich orange or yellow in colour. Adults are similar but not quite so brilliantly coloured as the juveniles, though still impressive fish. At up to 30 cm in length, this is a medium-sized species that can work well with peaceful tankmates of comparable size. A typical Rio Xingu fish in terms of care: it prefers above average temperatures and water that is soft and slightly acidic.
L018 is the popular "Gold Nugget Plec", Baryancistrus xanthellus. Dark green in colour and covered with small yellow spots and sporting fins edges with yellow, these are beautiful fish, and at around 30 cm in length adults are very impressive animals. Like L014, this is another Rio Xingu fish, needing warm, soft, and acidic water to do best. Baryancistrus typically inhabit fast-flowing waters and this species is no exception, so the water quality needs to be excellent and a strong water current certainly advisable. Otherwise not especially difficult to keep, though territorial towards its own species and sometimes other bottom-dwelling catfish. They are omnivores rather than algae eaters, and enjoy catfish pellets and frozen foods such as bloodworms, though some vegetable fooods, such as courgette, should be provided.
L024 is known as the "Flame Plec", Pseudacanthicus pitanga. This genus of loricariid are unusual in being fairly carnivorous, feeding as much on invertebrates as on algae and vegetables. Shelled mussels and prawns are particularly popular with these fish, though standard plec foods as well as sliced vegetables should be provided as well. Though predatory, they do not attack fish, and are perfectly safe with tankmates of similar size. Overall colour is ochre, with the fins, particularly the tail fin, having an orangey hue. Grows to around 30 cm in length. Pseudacanthicus are very territorial and should not be expected to share the bottom of the tank with other catfish of their own species or any other.
L025 is another species of Pseudacanthicus and very similar to L024 in terms of care. It is distinguished by having red rather than orange fins and by being much larger (45 cm) when mature.
L047 is now described as, Baryancistrus chrysolomus from the Rio Xingu, this time offered as the "Mango Plec". Basic colour is greenish grey with brilliant yellow markings on the pectoral, dorsal, and tail fins. Juveniles are especially attractive fish, but at up to 28 cm in length, the adults will need a fair amount of space. Care is similar to L018.
L075 was recently named Peckoltia sabaji. It is a medium sized species (around 25 cm) but surprisingly shy, and best kept with smaller fish such as tetras and Corydoras rather than with other catfish or cichlids of equal size. It is an attractive fish, pale brown with dark brown spots, with the fins being orange to red in colour. Not particularly territorial, it can be kept with its own species provided the fish are not overcrowded. As with other Peckoltia, provide a mix of algae and meaty foods.
L081 is a species of Baryancistrus sold as "Gold Nugget Plecs" like L018, but with slightly different colouration.
L134 is one of the smaller Peckoltia and is sometimes sold as the "Leopard Frog Pleco". A beautiful fish with alternating dark and light bands all along the body, it isn't far off the Zebra Plec in terms of striking colouration. As with other Peckoltia, this is an omnivore rather than an algae eater, but is otherwise a nice fish for the aquarium and not particularly territorial.
L172 is one of the more taxonomically obscure L-numbers that hasn't even been assigned to a genus let alone a species! Not very much more is known about its biology, though it is said to get to about 20 cm in length and is closely related to the the popular Ancistrus catfish ("Bristlenose Catfish") and may be assumed to be broadly similar in general care. Juveniles are greenish-brown in colour with small yellowy-white spots; adults likely to be similar but less strongly coloured.
L177 is yet another Baryancistrus sold under the "Gold Nugget Pleco" monicker.
L254 is a member of the genus Spectracanthicus, a group that is not overly familiar to aquarists. A striking fish, this species is dark grey in colour with widely space white spots. Coming from the Rio Xingu, this is one of the plecs that is not as adaptable as most, and needs warm, soft, and acidic water conditions to do well. Though not widely kept, it is known to be a safe community species and at around 10 cm in length when fully grown makes an especially good choice for an Amazon-themed community tank.
L260 is known as the "Queen Arabesque Plec" to aquarists but Hypancistrus sp. to scientists. A superb catfish, this species is always in demand. Attractively marked with thin white lines over a dark greyish-brown background, it gets to about 9 cm in length making it an ideal community tank species. A definite omnivore, this fish will eat a range of foods from bloodworms and small chunks of mussel and prawn through slices of softened vegetables and standard plec flakes and pellets. The only catch with these species is that it is intolerant of poor water quality, and both strong filtration and a high oxygen concentration are essential.
L262 is another Hypancistrus and though similar in terms of care, but instead of squiggles it is covered in cream-coloured spots.
LDA33 (also known as L142) is an underscribed species of Baryancistrus, a genus of catfish that naturally inhabit fast-flowing waters. As such, these is not a species for the overstocked aquarium or one with little water movement; instead, keep this fish in a tank with lots of water current provided by multiple powerheads or a strong canister filter. Additional aeration using a venturi or airstones is probably a good idea, as well. This species is very handsome, being dark grey to black in colour and peppered with large white spots. It gets to about 25 cm in length.