Common Pleco (Hypostomus plecostomus)

The Classic Algae-Eating Armoured Catfish

The Common Pleco (Hypostomus plecostomus) is one of the most recognisable freshwater fish in the hobby — a heavily armoured, sucker-mouthed catfish that has been a staple of the aquarium trade for decades. Excellent at grazing algae off glass, rocks, and driftwood, the Common Pleco is a hardworking bottom dweller that adds both function and character to larger aquariums.

Available in multiple sizes — from small juveniles to large, impressive adults — making it easy to find the right fit for your setup.

Overview

Size Guide

• S — approx. 1.5 in (4 cm)
• SM — approx. 2 – 2.5 in (5 – 6 cm)
• M — approx. 3 in (7.5 cm)
• L — approx. 4–6 in (10–15 cm)

Important: Tank Size Consideration

The Common Pleco is one of the most frequently outgrown fish in the hobby. Juveniles are often purchased for small tanks, but adults can reach over 40 cm and require a very large aquarium (300 L / 75 gallons or more). Please plan for their full adult size before purchasing. They are a long-lived species — up to 15 years — and deserve a suitable long-term home.

Water Parameters

• Temperature: 22 – 28°C (71.6 – 82.4°F)
• pH: 6.5 – 7.2
• General Hardness (GH): 3 – 10 dGH
• Carbonate Hardness (KH): 1 – 2
• TDS: 100 – 300 ppm

Tank Setup

• Tank Size: 200 L (50 gallons) minimum for juveniles; 300 L+ for adults
• Filtration: Strong filtration essential — plecos are heavy waste producers
• Decor: Driftwood is highly recommended — plecos rasp on wood as part of their diet and digestive process
• Hiding spots: Caves, PVC pipes, or large driftwood pieces for shelter during the day
• Lighting: Prefers dimmer conditions; most active at night

Diet & Feeding

• Primary: Algae grazing on tank surfaces, glass, and decor
• Supplement: Sinking algae wafers, blanched zucchini, cucumber, spinach, and spirulina wafers
• Driftwood: Should always have access to driftwood to rasp on
• Treats: Occasional sinking pellets or frozen bloodworms

Do not rely solely on algae for nutrition — supplement regularly with vegetable-based sinking foods.

Compatibility & Tank Mates

• Peaceful with most community fish occupying upper water levels
• May become territorial with other plecos or bottom dwellers — provide ample space and hiding spots
• Avoid keeping with very small fish as adults due to size difference

The Common Pleco is a hardy, long-lived, and endlessly useful aquarium fish — just make sure you’re ready to grow with it.