L091 Three Beacon Pleco (Leporacanthicus triactis)

Meet the L091 Three Beacon Pleco

The L091 Three Beacon Pleco (Leporacanthicus triactis) is a large armoured suckermouth catfish from the upper Orinoco River basin in Colombia and Venezuela. Its body shades from brown or grey to charcoal black depending on age, sex, mood and surroundings, and each of its three unpaired fins carries a vivid orange to yellow blotch: one on the dorsal fin, one on the small adipose fin behind it and one on the tail. Those three flashes of colour are the "beacons" in its common name.

It belongs to the family Loricariidae and to Leporacanthicus, the genus aquarists call vampire plecos. Every member has two long, fang-like teeth in the upper jaw and a small, blunt, backward-facing thorn on top of the head. Unlike many patterned plecos, the Three Beacon Pleco keeps its markings as it grows. Seriously Fish notes that the colour does not fade with age, and Planet Catfish adds that adults are a little paler in the body than youngsters, so the orange stands out even more on a grown fish.

Check the names on the label

Planet Catfish records that L091 has no other L-number "synonyms", which is unusual among plecos, so the code and the scientific name point to one fish. Colour forms with more or less orange in the fins are traded under names such as "dragon fin" and "tiger fin", but they are all L. triactis. Browse the other vampire plecos in our Leporacanthicus category, every coded catfish in our L-number plecos range, the wider South American catfish category or our full catfish and plecos collection.

Know what one purchase supplies

One purchase supplies one live Three Beacon Pleco at the standard size offered on this listing. Whatever its length on arrival, it is the same species that grows to about 25 cm, so make every decision about the aquarium for the adult fish rather than for the one in the bag.

Sex is not specified. Planet Catfish describes adult males as having a much longer and broader head, small bristle-like odontodes on the sides of the head, more odontodes on the pectoral-fin spine and body, a bigger dorsal fin and usually brighter colour. These differences only show reliably in mature fish, so do not plan around receiving a particular sex.

The photographs show the species, not the individual you will receive. The body shade and the size of the orange blotches vary from fish to fish and change with mood and lighting, so expect some difference from the pictures.

Plan from the adult, not the sale size

• Adult length: about 24.5–24.7 cm standard length (body length without the tail): Seriously Fish gives 245 mm, Planet Catfish 247 mm and FishBase 24.7 cm.
• Aquarium: a base of at least 120 × 45 cm for one fish.
• Temperature: 24–27°C, held steady.
• Social plan: one fish per tank unless there is room for separate territories, because it is territorial towards its own kind.
• Diet: a varied, meat-leaning diet with some vegetables.

Before ordering, read our delivery and Live Arrival Guarantee information and have the aquarium running and mature, so the fish goes straight into stable water.

Plan the aquarium around a 25 cm adult

Seriously Fish recommends an aquarium with a base of at least 120 × 45 cm for L. triactis; at 45 cm tall that is about 243 litres. Treat this as the minimum for a single fish. A large pleco uses floor space rather than height, so do not swap the stated footprint for a taller, narrower tank that happens to hold a similar number of litres.

Extra fish need extra floor. This pleco claims a cave and the ground around it, and Seriously Fish says a group can only be kept where there is plenty of space and several possible territories. If you add other bottom dwellers, each needs its own share of the base as well.

Use a three-step space check

1. Measure the base: confirm at least 120 cm long and 45 cm from front to back.
2. Map the territories: plan one cave for this pleco plus a separate retreat for every other bottom-dwelling fish, spaced so they are not all crowded into one corner.
3. Count the waste: use the full adult size of every fish when you choose the filter, because a 25 cm pleco produces far more waste than its sale size suggests.

Our tank volume calculator turns your tank's dimensions into litres, which you need for the filter, heater and water-change sums on this page. Our pleco care guide covers the basics that apply to every suckermouth catfish.

Build a fast-water layout with caves

In the wild this is a fish of rapids and fast-flowing water, where it lives among rocks and snags of driftwood. FishBase records that it is known to live in burrows, and Seriously Fish describes wild fish spawning in deep holes in river banks during the wet season. Recreate that with strong water movement, a soft floor and plenty of dark hiding places.

Divide the tank by function

Set heavy rocks and caves directly on the glass before you add sand, so digging cannot undermine them, and check that nothing can topple when a large fish pushes against it. Leave gaps between pieces of décor so a siphon can reach the floor.

Plants are optional. If you want greenery, choose tough plants attached to wood or rock rather than delicate rooted stems, because a strong pleco moving through the layout can dislodge them. Seriously Fish's advice centres on sand, rocks, driftwood and shade rather than plants, so a plant-free river layout suits it perfectly.

Set water values within the published range

Seriously Fish and Planet Catfish both give 24–27°C and pH 6.0–7.6, and Seriously Fish gives a general hardness of 2–15 dGH. ScotCat's older factsheet suggests a cooler 22–25°C and a narrower pH of 6.5–7.2, so the sources do not fully agree. We suggest working within the 24–27°C range that both current profiles give, and above all keeping it steady: Seriously Fish lists a stable temperature as one of this fish's needs.

Separate habitat values from waste readings

The waste limits come from OATA's catfish care sheet. They answer a different question from pH and hardness: water can sit inside the right pH range and still be unsafe because ammonia or nitrite has built up.

UK tap water varies a great deal from region to region. Soft and moderately hard supplies fall inside 2–15 dGH, while parts of southern and eastern England have very hard water that can reach the top of that range or beyond; blending with reverse-osmosis water brings it down. Your water company publishes the hardness for your postcode. Always treat tap water with a conditioner that removes chlorine and chloramine. Our water matcher compares your readings with this fish's range, and our water chemistry guide explains what each reading means.

Filter and oxygenate for a heavy waste load

Seriously Fish stresses two things for this species: highly oxygenated water with good movement, and an efficient filter to cope with the large amount of waste a big pleco produces. For a 243-litre tank it suggests a filter rated at roughly 970–1,215 litres per hour, which is four to five turnovers of the tank volume an hour, and about 100–175 W of heating split across two heaters, assuming a room near 20°C. Powerheads or large airstones add the extra current and oxygen of its rapids home.

Protect the heaters, as OATA advises for tanks with large fish, so the pleco cannot rest against or dislodge them. Keep the tank out of direct sunlight and away from draughts so the temperature stays stable.

Follow a weekly maintenance sequence

1. Test ammonia, nitrite and nitrate before you start, so the readings show the tank as it really is.
2. Change at least 25% of the water every week, as OATA recommends.
3. Treat the new water with a tap-water conditioner and match its temperature before adding it.
4. Siphon waste from the sand, especially around caves and behind wood where pleco droppings collect.
5. Check the filter and powerheads for blocked intakes and reduced flow.
6. Rinse filter media in removed tank water, never under the tap, so the beneficial bacteria survive.

If ammonia or nitrite reads above zero, test again, check the flow and review how much you are feeding before changing anything else. Clear water is not proof of safe water.

Feed a varied, meat-leaning diet

Do not buy this pleco to clean up algae. Planet Catfish describes it as "not a true vegetarian", and Seriously Fish says it prefers meaty foods while also taking algae and other vegetable matter. Seriously Fish suggests its fang-like teeth probably help it grip prey such as snails and other invertebrates, and Planet Catfish notes that shelled crustaceans and molluscs are dispatched with alarming ease.

Build the diet on good sinking foods such as carnivore pellets, catfish tablets and algae wafers. Add frozen or live bloodworm, chopped mussel and prawn or shrimp several times a week, and offer greens such as cucumber or courgette regularly, as both profiles recommend. Planet Catfish suggests using shelled crustaceans and molluscs sparingly, as a conditioning food rather than the everyday staple.

Build one measured meal

• Main portion: sinking pellets or tablets the fish clears within a few minutes; OATA allows up to 30 minutes for grazing species.
• Protein: on some days, a small portion of thawed frozen bloodworm, mussel or prawn instead of part of the pellets.
• Greens: a slice of cucumber or courgette weighted to the floor, with leftovers removed the next morning.
• Timing: feed once a day, close to lights-out, when a shy new pleco is most likely to come out.

Check the belly when it rests on the glass: a well-fed pleco looks rounded, while a hollow belly means it is not getting enough. In a busy community, place food near its cave so faster fish cannot take it all first.

Introduce it to a mature aquarium

Add the fish only to a tank that has been running long enough for the filter to mature, with ammonia and nitrite at zero and the temperature already inside 24–27°C. OATA recommends the floating-bag method: switch the aquarium lights off, float the sealed bag for about 10 minutes so the temperatures match, then add small amounts of tank water to the bag over up to 20 minutes before releasing the fish with as little bag water as possible. Our guide on how to acclimatise new fish walks through each step.

Handle it gently. Like most catfish it has sharp fin spines, and OATA advises double-bagging catfish so the spines cannot puncture the bag. Its bristly odontodes also catch easily in netting, so guide it into a container or bag rather than lifting it out in a net.

Use a first-week checkpoint plan

Expect it to spend the first days hidden. A settled pleco usually starts exploring after dark; continued refusal to eat, heavy breathing or a hollow belly after the first week are reasons to test the water and contact us.

Choose tank mates that respect its territory

Seriously Fish describes the Three Beacon Pleco as territorial, especially towards its own kind, and says males are more territorial than females. Planet Catfish adds that it gets on with small, lively catfish but that you should avoid too many other larger bottom dwellers unless space allows, because of disputes over territory.

Seriously Fish suggests characins, peaceful South American cichlids, Corydoras and other loricariids as companions. In a high-flow river tank it names headstanders (Anostomus), Hemiodus and current-loving cichlids such as Retroculus and the African Steatocranus. From our range, the Striped Headstander and the Lionhead Cichlid fit that river-tank style; check each fish's own water range with our tank mates tool before mixing.

Screen companions with suits and avoid

If you love vampire plecos, compare it with the L074 Galaxy Pleco, the L007 Galaxy Pleco and the L264 Sultan Pleco, which share the genus's fang-like teeth and head thorn. Treat them as alternatives rather than tank mates unless you can give each its own territory.

Watch for health problems early

Seriously Fish advises checking any pleco for a rounded belly and eyes that are not sunken, because emaciation is common in newly imported fish. Keep watching those two signs after arrival, along with the general warning signs OATA lists for all catfish: changes in swimming, colour, breathing, appetite, hiding and body condition.

Pair each observation with an action

Do not diagnose from one sign alone. Similar behaviour can follow poor water, low oxygen, bullying or hunger, so test first and change one thing at a time. If white spots appear, our white spot treatment guide explains the next steps; read any medicine's label for warnings about catfish before using it.

Understand the breeding record

The sources disagree on whether this species has been bred in aquariums. Seriously Fish says it is not known to have been bred in the hobby, but Planet Catfish has published a keeper's account of a spawning. In that report four adults of about 20 cm (8 inches) shared a large show aquarium; after a water change, a male guarded roughly 150 eggs inside a large clay drainage pipe blocked at one end with slate. The water was about 27°C (80°F) at pH 6.8. Many eggs were lost to fungus, but around twelve fry were raised and reached about 4–5 cm (1.5–2 inches) within three to four months.

In the wild, Seriously Fish describes spawning in deep holes in river banks during the wet season. Planet Catfish's catfish-of-the-month article suggests that the orange "beacons" may help females find occupied burrows in murky water, though the author presents this as his own idea rather than a tested fact.

Set up for a possible spawning

• Keep adults in a large aquarium with more caves than fish, including pipes just longer than the fish.
• Feed well on meaty foods so both sexes come into condition.
• Expect squabbling between a male and a female; the Planet Catfish keeper saw fights before each spawning attempt.
• Be ready to protect eggs from fungus; that keeper moved the eggs to an egg tumbler.

Answer Three Beacon Pleco buying questions

What is a Three Beacon Pleco?

It is Leporacanthicus triactis, coded L091, a vampire pleco from the upper Orinoco River basin in Colombia and Venezuela. It has a brown, grey or charcoal body and a vivid orange to yellow blotch on each of its three unpaired fins: the dorsal fin, the adipose fin and the tail.

How big does an L091 pleco grow?

About 24.5–24.7 cm standard length: Seriously Fish gives 245 mm, Planet Catfish 247 mm and FishBase 24.7 cm. Plan for a fish of roughly 25 cm plus its tail.

What size aquarium does it need?

Seriously Fish recommends a base of at least 120 × 45 cm, about 243 litres at 45 cm tall, for one fish. A group or other large bottom dwellers need more floor space and more caves.

Will a Three Beacon Pleco eat algae?

Only a little. Planet Catfish describes it as not a true vegetarian, and Seriously Fish says it prefers meaty foods. Feed sinking pellets, frozen foods such as bloodworm, mussel and prawn, and some vegetables.

Can it live with shrimps and snails?

Not safely. Its fang-like teeth make easy work of shelled crustaceans and molluscs, which it treats as food.

Can I keep more than one L091?

Only in a large aquarium with several caves and separate territories. Seriously Fish says it is territorial, especially towards its own kind, and that males are more territorial than females.

Does it keep its orange colour as it grows?

Yes. Seriously Fish and Planet Catfish both note that the orange flashes stay into adulthood, and adults are slightly paler in the body than youngsters, so the orange stands out well.

What water conditions does it need?

Seriously Fish and Planet Catfish give 24–27°C and pH 6.0–7.6, and Seriously Fish gives 2–15 dGH. Add strong flow and high oxygen, keep ammonia and nitrite at zero, and keep nitrate no more than 20 mg/l above your tap water.

Consult the care references

• Seriously Fish: Leporacanthicus triactis — size, aquarium base, water range, décor, oxygen and flow, diet, territorial behaviour, tank mates, sexing and wild spawning.
• Planet Catfish: Leporacanthicus triactis (L091) — names, type locality, size, identification of the three orange blotches, sexing, water values, feeding and compatibility.
• Planet Catfish: Catfish of the Month, Leporacanthicus triactis — catfish-of-the-month article on the genus, the teeth and head thorn, colour change with age and the idea behind the "beacons".
• Planet Catfish, Shane's World: Making beacons, the spawning of L091 — a keeper's report of an aquarium spawning, with egg numbers, cave type, water values and fry growth.
• FishBase: Leporacanthicus triactis — classification, distribution, maximum length, burrow-dwelling habit and conservation status.
• ScotCat factsheet: Leporacanthicus triactis — older factsheet with a cooler temperature range and narrower pH, and the 1992 L-number history.
• OATA: How to look after freshwater catfish — UK guidance for catfish on water quality limits, testing, maintenance, acclimatisation, feeding and warning signs.
• Tropical Fish Co delivery policy — current dispatch days and Live Arrival Guarantee terms.