Chaetodon decussatus also known as Blackened butterflyfish, Crisscross Butterflyfish and the Indian vagabond butterflyfish is as the name already says to find in the whole eastern Indian Ocean to Thailand and Indonesia. Inhabits coral reefs at depths of 2 to 20 m; Coastal bays, Lagoons, Reef external slopes and Reef flats.
Chaetodon decussatus is one of the large grown butterflyfish (20 cm - 8 inches), very similar to Chaetodon vagabundus, only with black dorsal and anal fins. Rarely exported through the aquarium trade.
The Vagabond Butterfly prefers a tank with plenty of places to hide & swim. He may act semi-aggressively toward other fish. In the wild he feeds on anemones, coral polyps, worms and algae.
Butterflyfish are not recommended for reefs as they will pick at or eat a wide variety of corals, fan worms, and other invertebrates. Most Butterflyfish are known to pick at Aiptaisia, a parasitic anemone.