Red Soapfish

The Red Soapfish (Suttonia lineata) is a distinctive marine predator. A small, cryptic fish with dark red to reddish-brown coloration, irregular mottling, and a paler lower face, it spends much of its time within shaded reef structure.

Indo-Pacific. It is associated with reef structure and nearby sheltered bottom habitat, using cover while resting or watching for prey. A mature aquarium with secure shelter and a reliable feeding routine allows its natural behavior to be observed without placing smaller livestock at unnecessary risk.

Plan housing around the adult fish. Its small size does not make it harmless to tiny shrimp or fish fry. Soapfish defensive secretions are an additional handling concern: avoid harassment, minimize handling, and transfer separately.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 20 Gallons
Adult Size: Up to 3.2 inches (8.1 cm standard length)
Temperament: Peaceful
Diet: Carnivore
Reef Safe: With Caution
Region: Indo-Pacific
Scientific Name: Suttonia lineata

Tank Requirements

Provide an established aquarium of at least 20 gallons for adult housing, with larger systems preferred. The footprint must allow comfortable turning and full access to shelter. Its small size does not make it harmless to tiny shrimp or fish fry. Soapfish defensive secretions are an additional handling concern: avoid harassment, minimize handling, and transfer separately.

Build several shaded caves, ledges, and visual barriers while leaving open areas for feeding. Use moderate, broadly distributed circulation and protected resting areas. A mature biological filter, good oxygenation, and a fitted cover support a stable, secure environment.

Make shelter entrances wide enough for growth and keep rock structures stable. Avoid repeated rearrangement during settling. A fish spending most of its time under cover still needs room to turn and emerge without scraping against decorations.

Diet and Feeding

Offer small mysis shrimp, enriched brine shrimp, copepods, finely chopped marine seafood, and quality small carnivore preparations when accepted. Provide two or three modest meals daily near shelter, and verify that this cryptic fish actually swallows food.

Use a feeding routine that lets you observe intake and condition. Do not leave uneaten seafood inside caves or encourage feeding to extreme fullness. Remove remains promptly and investigate sustained refusal, rapid breathing, or visible weight loss rather than simply offering larger quantities. Keep hands away from the mouth and use appropriate feeding tools.

Temperament and Tankmates

Generally peaceful toward appropriately sized unrelated fish, it needs calm companions that will not chase it or intercept every meal. Its large mouth relative to its body still puts very small fish and shrimp at risk. Provide several separate retreats and avoid assuming two unpaired individuals will coexist in a confined space.

Watch for blocked access to caves, injuries, and persistent hiding after a new introduction. Feeding the predator well does not make prey-sized tankmates safe, and apparent juvenile compatibility may change as fish mature.

Reef Compatibility

Reef safe with caution. Coral tissue is not its usual food, but tiny shrimp, fish fry, and other prey-sized animals can be consumed. A coral-focused aquarium can work only when the livestock and feeding routine suit this fish's needs.

Water Parameters

Temperature: 75–79°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Maintain stable, well-oxygenated marine water with undetectable ammonia and nitrite. Match acclimation to the supplier's holding conditions, avoid rapid changes, and maintain filtration for the actual feeding load.

Common Considerations

• Adult commitment: Up to 3.2 inches (8.1 cm standard length). Plan the aquarium and every tankmate accordingly.
• Food and filtration: Varied marine nutrition and prompt waste removal support long-term condition.
• Shelter: Provide secure retreats with comfortable adult clearance.
• Predation: Mouth-sized fish and mobile invertebrates are at risk.
• Species considerations: Its small size does not make it harmless to tiny shrimp or fish fry. Soapfish defensive secretions are an additional handling concern: avoid harassment, minimize handling, and transfer separately.