DescriptionA deep-bodied butterflyfish with a rounded profile, the Chaetodon semilarvatus reaches an adult size of approximately 20–23 cm (8–9 inches). Its body is a brilliant golden yellow adorned with thin, vertical blue lines and a distinctive blue facial patch—hence the common name “Bluecheek Butterflyfish.”In pairs, these fish often swim closely side by side, forming strong social bonds that can last for life.Aquarium RequirementsMinimum Tank Size: 450 litres (120 US gallons) for a single specimen; 680 litres (180 US gallons) or larger for a bonded pairTemperature: 24–28 °C (75–82 °F)pH: 8.1–8.4Specific Gravity (Salinity): 1.020–1.025Alkalinity: 8–12 dKHAmmonia & Nitrite: 0 ppmNitrate:< 20 ppmAquascape and Environment:Provide a large, mature aquarium with ample live rock for grazing and hiding. Open swimming space is important, as the Addis Butterflyfish is an active species that spends much of its time gliding through midwater zones. Incorporate branching corals, caves, and overhangs to mimic its natural reef habitat.Maintain excellent water quality and stable conditions—this species is sensitive to fluctuations in temperature and salinity. Moderate water flow and strong oxygenation are ideal.Diet and FeedingIn the wild, the Addis Butterflyfish feeds primarily on coral polyps, small benthic invertebrates, and algae. In captivity, dietary adaptation can take time, but success is achievable with a variety of nutritious offerings.Recommended Foods: Frozen mysis and enriched brine shrimp Finely chopped seafood such as clam, shrimp, or squid Specialized sponge-based frozen formulas for butterflyfish and angelfish Marine omnivore pellets and flakes (once acclimated) Live blackworms or small live foods to stimulate feeding Feed 2–3 times daily in small portions. Initial feeding success often improves when live rock is present, allowing the fish to graze naturally between meals.Temperament and CompatibilityThe Addis Butterflyfish is peaceful and generally non-aggressive toward other species, though it may defend its territory from other butterflyfish or similar-looking species. It thrives either singly or as part of a bonded pair.Suitable Tankmates: Peaceful community reef fish (e.g., tangs, wrasses, anthias, gobies, and fairy basslets) Other non-aggressive butterflyfish in large tanks (600+ litres) Small to medium angelfish (with caution) Avoid: Aggressive or territorial species such as triggers, dottybacks, or large wrasses Other coral-feeding butterflyfish in small systems Reef Compatibility⚠️ Not Reef SafeThe Addis Butterflyfish is known to feed on live coral polyps, particularly from stony coral species (SPS and LPS). It is best suited to FOWLR aquariums rather than mixed reef tanks. If corals are present, expect potential nipping or grazing activity.Additional InformationMaximum Size: 20–23 cm (8–9 inches)Lifespan: 8–10 years in captivity (with excellent care)Difficulty Level: Moderate to Difficult (requires mature system and specific diet)Natural Behaviour: Graceful swimmer, often found in pairs; coral grazerOrigin: Red Sea and Gulf of AdenColouration: Golden yellow body with blue vertical lines; bright cobalt-blue patch behind each eye; translucent finsSummaryThe Addis Butterflyfish (Chaetodon semilarvatus) is a magnificent and iconic species from the Red Sea, admired for its vibrant coloration and regal presence. While not suitable for reef aquariums due to its coral-eating habits, it can thrive in a spacious, mature marine system with high water quality and a carefully planned diet. Ideal for experienced aquarists, this species rewards proper care with beauty, grace, and fascinating pair-bonding behaviour—an unforgettable centerpiece for large marine displays.
