L027D Tapajos Royal Pleco (Panaque armbrusteri)

Meet the L027D Tapajos Royal Pleco

The L027D Tapajos Royal Pleco is Panaque armbrusteri, a heavy-bodied, wood-eating royal panaque from the Rio Tapajós and its tributaries in Brazil. It was formally described in 2010 by Nathan Lujan, Max Hidalgo and Donald Stewart in a revision of the royal plecos published in the journal Copeia, and named in honour of the ichthyologist Jonathan W. Armbruster. The type specimen, 344.7 mm long, came from the Teles Pires River in Mato Grosso, part of the Tapajós system.

Its pattern is its signature: alternating dark brown-to-black and paler beige-to-grey stripes run lengthwise from the snout to the tail, and the fins are striped like the body. Planet Catfish describes the base colour as brownish black with beige stripes, and explains its other trade name, the Thunder Royal Pleco: it comes from a Japanese word covering both lightning and thunder, a nod to the lightning-like pale stripes seen especially on larger fish.

Read the codes and names correctly

Tell it apart from other royal plecos

The 2010 revision separates P. armbrusteri from its relatives by a modest hump behind the head, more teeth in each jaw, relatively short pectoral and pelvic spines and a flared bone below the eye. It also found something unique among plecos: as the fish grows, the left and right tooth rows open out from about 90 degrees in fish under 172 mm to about 120 degrees in fish over 200 mm. Young fish under about 114 mm have a clear "window" in the dark tail fin, which shrinks until the adult tail is fully dark; the tail sometimes has a yellow-orange rear edge.

The authors of the revision note that the Xingu, Tocantins and Araguaia populations may be the same species but kept them out of their study, which is why those fish still carry "cf.". Browse every species in our Panaque category, all coded catfish in our L-number plecos range, the wider South American catfish category, our centrepiece fish or the full catfish and plecos collection.

Know what one purchase supplies

One purchase supplies one live L027D Tapajos Royal Pleco at the standard size offered on this listing. Expect a young fish, possibly still showing the clear window in its tail, and plan the aquarium for an adult of around 35–40 cm.

Sex is not specified. Planet Catfish describes males with heavy odontode growth on the pectoral fins and long cheek spines; the 2010 description shows these hooked cheek odontodes can be flared out to about 90 degrees. These differences only develop in large, mature fish.

The photographs show the species, not the individual you will receive. Stripe width, contrast and tail markings vary from fish to fish and change with age.

Plan from the adult, not the sale size

• Adult length: Planet Catfish gives 400 mm standard length (body length without the tail); FishBase gives 43 cm total length and 1.3 kg.
• Aquarium: ScotCat says a grown royal panaque needs a 5–6 ft (about 150–180 cm) tank.
• Temperature: 23–27°C.
• Diet: driftwood at all times, plus vegetables, tubers and algae wafers.
• Filtration: heavy, around six tank turnovers an hour as ScotCat suggests.

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.

Give it a long, deep floor

This pleco lives on the bottom and among wood, so floor area is what it uses. ScotCat's royal panaque factsheet says a fully grown fish needs a 5 or 6 ft aquarium, about 150–180 cm long, to function properly. OATA includes the larger plecos among its "tank busters" and says they need an exceptionally large aquarium, often well over 500 litres, warning that an off-the-shelf tank is unlikely to be big enough for the long term.

Start with the largest base you can and plan upgrades early. Royal plecos are slow-moving and long-lived, and a cramped tank shows up as poor water quality long before the fish looks too big.

Use a three-step space check

1. Measure the base: aim for 150–180 cm long with a generous front-to-back depth.
2. Plan the wood: leave room for several large pieces of driftwood and one cave or root overhang as its home base.
3. Count the stock: add up the adult sizes of every fish before you buy tank mates.

Our tank volume calculator converts your tank's measurements into litres, and our stocking calculator shows how much capacity a fish this size uses before you add anything else.

Recreate a tangle of fallen trees

Planet Catfish describes the natural habitat as fallen trees and wood tangles. The revision explains why wood matters so much: Panaque teeth are short and spoon-shaped, wider at the tip, and the authors compare them to the head of an adze, a tool made for gouging wood, driven by greatly enlarged jaw muscles. Within its group, P. armbrusteri has the most teeth of all, and the authors call it one of the most specialised members.

Divide the tank by function

Use dense, well-soaked hardwood that sinks, and wedge heavy pieces so they cannot roll. OATA warns that large fish can dislodge ornaments and advises securing all décor and fitting a fish-proof cover, because big fish can be jumpy when first moved.

Hold water values in the Tapajós range

Planet Catfish gives 23–27°C for P. armbrusteri. That is cooler than the 26–29°C it gives for the Xingu royal pleco, so do not assume every "L027" wants the same temperature. No pH or hardness range is published for this species; ScotCat gives pH 6.0–7.5 for the related royal panaque, P. nigrolineatus, which is a sensible working range. Above all, keep conditions steady.

Separate habitat values from waste readings

The waste limits come from OATA's catfish care sheet; for a fish that grazes all day they are the numbers to watch.

UK tap water ranges from soft to very hard depending on where you live, and your water company publishes the hardness for your postcode. Hard supplies can be softened by blending with reverse-osmosis water. Always treat new water with a conditioner that removes chlorine and chloramine. Our water matcher compares your readings with this pleco's needs, and our water chemistry guide explains each reading.

Filter and maintain for constant grazing

A fish that rasps wood around the clock produces a steady stream of waste. ScotCat recommends a large external filter that turns the tank volume over about six times an hour and gives a good current, and OATA says very large fish may need several large filters or even a pond filter to deal with solid waste. FishBase notes that Panaque can gulp air when oxygen runs low, but treat that as an emergency reserve: keep the water well aerated.

Protect heaters from damage, as OATA advises, and site the tank away from draughts and direct sunlight to keep the temperature even.

Follow a weekly maintenance sequence

1. Test ammonia, nitrite and nitrate before any work.
2. Change at least 25% of the water, OATA's weekly minimum; a fish this size benefits from more.
3. Condition the new water and match its temperature first.
4. Siphon the sand beside and under the wood, where fine wood particles and droppings settle.
5. Rinse pre-filter sponges in old tank water; they clog quickly with wood fragments.
6. Check heaters, guards and the cover are secure.

If ammonia or nitrite appears, test again, check the flow and reduce feeding before changing anything else.

Feed wood first, then vegetables

Planet Catfish lists the foods royal plecos take alongside wood: prepared algae wafers, fresh vegetables such as courgette, cucumber, peas and green beans, and tubers such as potato and yam. ScotCat adds that vegetable foods are a must and advises against frequent meaty frozen foods, because a royal panaque's long gut is built for greens.

Build one measured meal

• Constant: driftwood to rasp, never removed for cleaning all at once.
• Evening vegetables: a slice of courgette or cucumber, a few peas or green beans, or a piece of cooked potato or yam, weighted down near its retreat.
• Staple: algae wafers or vegetable tablets it clears within about 30 minutes, the allowance OATA gives grazing catfish.
• Rarely: a little frozen food as an occasional extra.

ScotCat notes that royal plecos hide by day and come out at night to search for food, so feed around lights-out and lift any leftovers in the morning. A rounded belly is the best sign that it is eating enough.

Settle it in calmly

Add the fish only to an aquarium with a mature filter, ammonia and nitrite at zero, the temperature already between 23 and 27°C and the driftwood in place. 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 covers each step.

Its hooked cheek odontodes and fin spines snag nets and can pierce bags, which is why OATA advises double-bagging catfish. Move it in a container rather than a net.

Use a first-week checkpoint plan

Share the tank with calm, large midwater fish

Planet Catfish describes P. armbrusteri as generally peaceful, though it may defend its territory against its own kind. ScotCat's advice for royal panaques is a large community with like-sized cichlids or large barbs that swim in the upper layers; it notes that even smaller relatives come to no harm, and that aggressive species should be avoided because they upset this peaceful catfish.

From our range, the Tinfoil Barb is a large barb for the upper water of a big tank and the Red Spot Severum a calm, sizeable cichlid. Check each one's temperature range against 23–27°C with our tank mates tool before mixing.

Screen companions with suits and avoid

If you are comparing royal plecos, see the L190 Golden Royal Pleco, the Royal Pleco (Panaque nigrolineatus), our L027 Royal Pleco, the L090 Papa Panaque and the L239 Blue Fin Panaque. Keep them as alternatives rather than tank mates unless each can have its own territory.

Spot health problems early

OATA lists the warning signs to watch in catfish: clamped fins, flicking against décor, shimmying, changes in breathing, colour or appetite, loss of condition and unusual hiding. In a royal pleco, a thinning belly or wood left untouched are the earliest clues that something is wrong.

Pair each observation with an action

Never diagnose from a single sign; poor water, low oxygen, bullying and hunger can look alike. If white spots appear, our white spot treatment guide explains the next steps, and our pleco care guide covers routine checks for every suckermouth catfish. Read any medicine's label for warnings about catfish before using it.

Understand its conservation and breeding status

FishBase and Planet Catfish give its IUCN Red List status as Least Concern, last assessed in 2018. Planet Catfish records no aquarium breeding of P. armbrusteri; its page for the related Araguaia royal pleco cites a 2013 Amazonas magazine report of a first captive royal pleco breeding, so spawning is possible in principle but very rare. Buy this fish as a long-term centrepiece for a large, wood-filled aquarium.

Answer Tapajos Royal Pleco buying questions

What is the L27D Tapajos Royal Pleco?

It is Panaque armbrusteri, a large wood-eating royal pleco from the Rio Tapajós and its tributaries in Brazil, described by Lujan, Hidalgo and Stewart in 2010. Planet Catfish lists it under the codes L027 and LDA077; UK shops sell it as L27D.

Why is it called the Thunder Royal Pleco?

Planet Catfish explains that the name comes from the English translation of a Japanese word covering both lightning and thunder, a reference to the lightning-like pale stripes that run along the body, especially in larger fish.

How big does a Panaque armbrusteri grow?

Large. Planet Catfish gives 400 mm standard length and FishBase 43 cm total length and 1.3 kg; the largest of the specimens studied in the 2010 description measured 345 mm standard length.

Does it need wood in the tank?

Yes, always. Planet Catfish says all Panaque appear to feed on wood, and the 2010 revision describes their spoon-shaped teeth as shaped like the head of an adze, a tool for gouging wood. Offer vegetables, tubers and algae wafers as well.

What size aquarium does it need?

ScotCat says a fully grown royal panaque needs a 5–6 ft aquarium, about 150–180 cm long, and OATA notes that very large fish often need well over 500 litres. Plan for the adult before you buy.

What temperature does it need?

Planet Catfish gives 23–27°C for P. armbrusteri. No pH is published for the species; ScotCat gives pH 6.0–7.5 for the related royal panaque.

How can I tell it from other royal plecos?

Look for alternating dark brown and paler beige-to-grey stripes running the length of the body, a modest hump behind the head and, in young fish, a clear "window" in the dark tail. The 2010 revision notes that its tooth rows widen as it grows, which is unique among plecos.

Is Panaque armbrusteri endangered?

No. FishBase and Planet Catfish give its IUCN Red List status as Least Concern, last assessed in 2018.

Consult the care references

• Planet Catfish: Panaque armbrusteri — Panaque armbrusteri: names (L027, LDA077, Tapajos and Thunder Royal Pleco), type locality, size, teeth, colour, sexing, distribution, temperature, wood diet, habitat and compatibility.
• Lujan, Hidalgo & Stewart 2010, Copeia: Revision of Panaque (Panaque) — peer-reviewed revision describing P. armbrusteri: teeth, stripes, juvenile clear tail window, eye colour in life, largest specimen and the Xingu, Tocantins and Araguaia populations.
• FishBase: Panaque armbrusteri — classification, distribution in the Tapajós basin, maximum total length and weight, air-breathing in the genus and conservation status.
• Planet Catfish: Panaque cf. armbrusteri "Xingu" — the Xingu royal pleco: names (L027 Xingu, L027A, LDA063), size, juvenile and adult colour, fin size, temperature, diet, habitat and compatibility.
• Planet Catfish: Panaque cf. armbrusteri "Tocantins" — the Tocantins (platinum) royal pleco: codes, juvenile and adult colour, eye colour and temperature, used for the comparison table.
• Planet Catfish: Panaque cf. armbrusteri "Teles Pires" — the Teles Pires royal pleco (LDA107): the spotted tail that sets it apart, used for the comparison table.
• Planet Catfish: Panaque cf. armbrusteri "Araguaia" — the Araguaia royal pleco and the 2013 Amazonas magazine report of a captive royal pleco spawning.
• ScotCat factsheet: Panaque nigrolineatus (Royal Panaque) — royal panaque factsheet for the related P. nigrolineatus: tank length, filter turnover, driftwood, night activity, vegetable diet, tank mates and sexing.
• OATA: How to look after freshwater catfish — UK guidance for catfish on water quality limits, testing, maintenance, double-bagging, acclimatisation and warning signs.
• OATA: How to look after very large fish (tankbusters) — UK guidance on very large aquarium fish: tank size, filtration, protected heaters, secure décor and a cover.
• Tropical Fish Co delivery policy — current dispatch days and Live Arrival Guarantee terms.