Royal Pleco & L-Number Plecos Care Guide

Home › Care Guides › Royal Pleco & L-Number Plecos Care Guide

Overview

The Loricariidae family — commonly known as armoured catfish or plecos — contains over 800 described species and represents one of the most diverse fish families in the world. Among hobbyists, the “L-number” system (introduced by German aquarists in the 1980s) is used to catalogue undescribed or newly discovered species, giving each a number such as L190 (Royal Pleco) or L191 (Large-spotted Royal Pleco).

Royal Plecos (Panaque nigrolineatus complex) are among the most impressive and desirable of all plecos — large, boldly patterned catfish with vivid red eyes and distinctive wood-eating habits. The Suttoni Blue Eye Panaque (Panaque cf. nigrolineatus “Suttoni”) is particularly sought after for its electric blue eye colouration and striking dark patterning.

These are long-lived, intelligent fish that form a strong bond with their owners. A well-kept Royal Pleco can live for 20+ years and become a true centrepiece of a large aquarium.

Natural Habitat

Royal Plecos and Panaque species inhabit the fast-flowing, oxygen-rich rivers and streams of the Orinoco, Amazon, and their tributaries. They are typically found clinging to submerged wood in areas with significant current — their sucker-mouth allows them to hold position in powerful water flow while rasping wood and biofilm.

Uniquely among fish, Panaque species are xylivorous — they actually digest wood using specialised gut bacteria, making driftwood an essential part of their diet rather than just décor.

Tank Requirements

• Minimum tank size: 300 litres for a single Royal Pleco; 500+ litres for a large adult or multiple specimens
• Filtration: High turnover is important — aim for 8–10× tank volume per hour through filtration. These fish produce significant waste
• Driftwood: Essential — not optional. Provide multiple pieces of Mopani or spider wood. Royal Plecos rasp and consume wood as part of their natural diet
• Current: Moderate to strong current is appreciated; powerheads or additional circulation pumps are beneficial
• Caves and hides: Royal Plecos are territorial and secretive. Provide PVC pipe, coconut caves, or purpose-built pleco caves (one per fish)
• Substrate: Fine sand or smooth gravel; these fish spend significant time on the substrate

Water Parameters

• Temperature: 23–29°C (26°C optimal)
• pH: 6.5–7.5
• Hardness: 2–12 dGH (softer is better; these are Amazonian fish)
• Ammonia/Nitrite: 0 ppm
• Nitrate: Below 30 ppm; plecos produce heavy waste so weekly 30–40% water changes are essential
• Oxygen: High oxygenation is important — add airstones or surface agitation if filtration alone is insufficient

Feeding

Royal Plecos are primarily herbivores and wood-eaters. Their diet in captivity should reflect this.

Ideal foods:

• Driftwood (always available — essential for digestive health)
• Blanched vegetables: courgette (zucchini), cucumber, sweet potato, spinach, kale
• Algae wafers (Hikari, Sera — high quality brands)
• Repashy Soilent Green gel food (excellent for plecos)
• Earthworms and bloodworm (occasional protein supplement)
• Raw, unshelled prawns

Royal Plecos are primarily nocturnal feeders. Drop food into the tank shortly before lights-out for best results. Vegetables should be removed after 24 hours to avoid fouling the water.

Tank Mates

Royal Plecos are generally peaceful toward fish that occupy different areas of the tank, but can be territorial toward other bottom-dwelling fish, especially other plecos.

Good choices:

• Arowana, Gars, large cichlids (occupy different areas)
• Large tetras and Silver Dollars
• Stingrays (with caution — ensure no territorial conflict over bottom space)
• Other L-number plecos of similar size (with ample cave territories)

Avoid:

• Multiple Royal Plecos in a small tank — territorial aggression is intense
• Aggressive bottom-dwelling cichlids like Texas or Flowerhorn

Breeding

Breeding Panaque species in captivity is challenging but has been achieved. They are cave spawners — the male guards and fans the eggs in a tight cave. Conditioning requires very high water quality, temperature consistency, and abundant food. Successful breeding is a notable achievement among pleco enthusiasts.

Common Health Issues

• Bloat/dropsy: Often caused by bacterial infection, usually triggered by poor water quality. Identify and address the root cause immediately.
• Hole-in-the-head disease: Associated with nutritional deficiency and poor water quality. Feed a varied diet and maintain pristine conditions.
• Ich: Treatable with standard ich treatments, though Royal Plecos are sensitive — use half-dose initially.

Where to Buy Royal Plecos in the UK

MTF Aquatics regularly stocks Royal Plecos (L190), L191, Suttoni Blue Eye Panaque, and a rotating selection of rare L-numbers from our transhipping network. Stock sells quickly — contact us or pre-order for the next tranship.