Harlequin sharkminnow

Labeo cyclorhynchus

Also known as Harlequin shark, Variegated shark, Calico shark

FreshwaterFish

Harlequin sharkminnow (Labeo cyclorhynchus) — The Wet Spot Tropical Fish · Used with permission

Care at a glance

Temperature: 73–81°F (23–27°C)
pH: 6.0–7.5
Adult size: 6.3 in (16 cm)
Minimum tank: 66 gal (250 L)
Temperament: Aggressive
Social behavior: Solitary
Tankmates: Tankmates with caution
Swim level: Bottom
Difficulty: Medium
Breeding: No record
Rarity: Rare
Origin: Congo basin
Family: Cyprinidae

Overview

Keep this fish one to a tank. It is a solitary, territorial grazer that claims a patch of the bottom and defends it hard, and it will not tolerate another of its kind or any similar shark-shaped fish, which it chases relentlessly. Tankmates need choosing with care: sturdy, dissimilar midwater and upper fish that stay out of its ground-level territory are fine, while other bottom dwellers and lookalikes are not. It works surfaces for algae and aufwuchs, so feed algae wafers, sinking pellets, and some meaty frozen foods. Give it 250 liters or more with caves, wood, and broken sightlines that split the floor into territories.

In the wild

The harlequin sharkminnow lives among wood and rock in tributaries of the Congo basin in central Africa, in warm, flowing water. Recreate that with a sandy floor, plenty of driftwood and rounded stone, and caves it can adopt as a base, with steady current. Keep it at 23 to 27 degrees Celsius, with a pH from 6.0 to 7.5. Broken-up hardscape that creates visual barriers helps take the edge off its territorial streak.

Good to know

Labeo cyclorhynchus is an African member of the carp family, Cyprinidae, reaching about 16 centimeters. It is patterned in mottled cream and black rather than the solid colors most of its relatives wear, and its species name means round snout. It fills the same aquarium niche as the Asian red-tailed and rainbow sharks, another sturdy, territorial cyprinid grazer. Its aquarium breeding is not documented, and adults are too aggressive to pair up easily.

Did you know

Most of its Labeo relatives wear plain, solid colors, so this fish stands out for its blotchy, camouflage-style pattern, the look that earns it the trade names harlequin and variegated shark.