Lined Tang (Acanthurus lineatus): Breeding Guide
Acanthurus lineatus lives in male-controlled harems and spawns in pairs within aggregations, releasing pelagic eggs over the reef. Its drifting larvae and intense aggression make home breeding impossible.
Overview
The Lined Tang, Acanthurus lineatus, ranges across the Indo-Pacific from East Africa and the Mascarenes to the Hawaiian, Marquesas and Tuamotu islands, north to southern Japan and south to the Great Barrier Reef. FishBase gives a maximum total length of 38 cm and a shallow depth range of 0 to 15 m, typically just 1 to 3 m in surge zones. Maturity is reached at about 18 cm.
It is among the most aggressive surgeonfishes toward conspecifics, which is why it is usually kept singly in very large systems. There are no records of captive breeding.
Sexing
FishBase reports that a large male controls well-defined feeding territories and harems of females. This social structure indicates a dominant, territory-holding male among a group of females, but no simple external feature for routine sexing is documented in the consulted sources.
Spawning Behavior & Trigger
According to FishBase, A. lineatus forms spawning aggregations but spawns in pairs. Unusually for the genus, spawning is diurnal: courtship occurs at various times of day, peaks in the morning and may continue from midday to afternoon, and is often confined to ebb tides that carry eggs off the reef.
A pair rises briefly off the bottom to release eggs and sperm into the water column. Fertilization is external and there is no parental care of the floating eggs.
Egg & Fry Care
Eggs are pelagic and disperse with the ebb-tide current. They hatch into transparent acronurus larvae that live in the plankton, a stage that in surgeonfishes can exceed 39 days before settlement.
The lengthy planktonic phase and dependence on ocean plankton mean larvae cannot be reared in a closed system. Surgeonfish larval culture remains limited to research aquaculture.
Common Challenges
- Extreme territoriality makes it unsafe to keep more than one specimen, so a spawning pair cannot be maintained at home.
- Pair spawning happens in open water with no clutch to collect or guard.
- Acronurus larvae require an extended pelagic drift on natural plankton that aquariums cannot supply.