Rusty Parrotfish (Scarus ferrugineus)
• Small fish safe: ✅ Yes (herbivorous diet; generally peaceful towards other fish)
• Small invert safe: ✅ Yes (feeds primarily on algae; poses little threat to invertebrates)
• Coral safe: ⚠️ With caution (may inadvertently damage corals while grazing on algae)
• Minimum tank size: 500 liters (130 gallons)
• Adult size: Up to 41 cm (16 inches)
• Diet: Herbivorous, feeding mainly on benthic algae
• Be aware of: Requires ample grazing areas; may change sex from female to male; needs stable water conditions
Appearance and Coloration
The Rusty Parrotfish exhibits distinct coloration patterns between its life phases. In the initial phase, individuals are predominantly brownish with light and dark bands and a yellow tail, which contributes to their “rusty” appearance. In the terminal phase, typically representing adult males, the fish display vibrant blue-green hues with multicolored patterns. This sexual dimorphism is common among parrotfish species.
Natural Habitat and Behavior
Native to the Red Sea, Gulf of Aden, and Persian Gulf, Scarus ferrugineus inhabits protected coral slopes at depths ranging from 1 to 60 meters. These fish are often observed in small groups, with terminal-phase males forming harems consisting of several females. They play a crucial role in reef ecosystems by grazing on benthic algae, which helps prevent algal overgrowth on coral structures.
Tank Requirements and Water Parameters
• Minimum Tank Size: 130 gallons (500 liters)
• Water Parameters:
• Temperature: 24°C – 28°C (75°F – 82°F)
• pH: 8.1 – 8.4
• Specific Gravity: 1.020 – 1.025
• Aquascaping:
• Provide abundant live rock to facilitate natural grazing behavior.
• Ensure stable rock structures to support their burrowing and foraging activities.
• Maintain open swimming spaces to accommodate their active nature.
• Lighting: Moderate to high, supporting algal growth for grazing.
• Water Movement: Moderate, simulating natural reef environments.
Diet and Feeding
As herbivores, Rusty Parrotfish primarily consume benthic algae, contributing to the health and balance of reef ecosystems. In captivity, it’s essential to replicate their natural diet to maintain their health and vibrant coloration.
• Natural Diet: Benthic algae scraped from coral and rocky substrates.
• Captive Diet:
• Offer a variety of marine algae, such as nori or seaweed sheets.
• Provide high-quality herbivore pellets or flakes enriched with spirulina.
• Supplement with fresh vegetables like blanched spinach or lettuce.
Feeding Frequency: Multiple small feedings throughout the day to mimic constant grazing behavior.
Compatibility and Social Structure
• Temperament:
• Generally peaceful and can coexist with a variety of tank mates.
• May exhibit territorial behavior, especially males during breeding seasons.
• Tank Mates:
• Compatible with other non-aggressive species such as tangs, wrasses, and dwarf angelfish.
• Avoid housing with overly aggressive species that may harass or outcompete them.
• Reef Compatibility: ⚠️ With caution—while they primarily feed on algae, their constant grazing may inadvertently damage delicate coral structures.
Important Considerations
• Sexual Dimorphism and Hermaphroditism: Rusty Parrotfish are protogynous hermaphrodites, meaning individuals start as females and can transition to males, especially in the absence of a dominant male. This transition is accompanied by a change in coloration and behavior.
• Contribution to Sand Production: Their feeding behavior involves scraping algae and ingesting calcareous material, which is later excreted as sand, playing a role in the bioerosion and sediment production on reefs.
• Active Lifestyle: Provide ample space and environmental enrichment to accommodate their need for constant grazing and exploration.