Papaya Fish

1 Species Overview

The papaya fish has a very special name and equally special looks. Its whole body is wrapped in a hard bony carapace that cannot move; only the mouth and caudal peduncle are free, so it moves very slowly.

English name: Papaya fish

Origin: Coral reef waters of the Indian Ocean and western Pacific

Reproduction: Egg-laying

Water: seawater hardness 7 to 9 dH; pH 8.0 to 8.5; specific gravity 1.022 to 1.023

Temperature: 26 to 27 C

2 Appearance and Physical Traits

When startled, the papaya fish releases toxin from its body, so it must not be kept with other ornamental fish, and it will also attack small fish.

The papaya fish is 10 to 15 cm long, wholly golden yellow with dense black round dots. The dorsal fin is moved back to the caudal peduncle, symmetrical with the anal fin. The eyes sit on top of the head. The whole body is wrapped in a hard bony carapace that cannot move; only the mouth and caudal peduncle are free to move. It swims slowly. Its esophagus is specially built so that when threatened or startled it gulps air and water, swelling the chest and belly like a ball with erect small spines, floating on the surface to play dead as defense; when safe it quickly releases the air and water and darts away. It also has a biting habit and, when caught, makes a ‘gugu’ sound.

3 Habitat and Living Environment

Keep the papaya fish away from tankmates and watch water quality; because it is special, when startled it releases toxin, so do not mix it with other fish.

1. Do not keep in freshwater; use seawater. Add salt as needed and check with a hydrometer. This fish has sharp teeth and attacks small fish; when facing a bigger fish or danger it releases toxin to kill enemies.

2. Though small, it will nip others’ fins, especially liking to bite the tails of other fish and even its own kind.

3. When conditions are poor (lack of food, high stocking density) papaya fish often kill each other, worst in the fry stage. Its skin is full of toxin; when threatened or startled it releases toxin to poison enemies, then darts away. It also has a biting habit and makes a ‘gugu’ sound when caught.

4. Temperature: 24 to 27 C, pH 8.1 to 8.4, seawater specific gravity 1.020 to 1.025.

4 Feeding Guidelines

Feed the papaya fish a balanced diet; never a single food, which causes refusal and harms health. Keep temperature and pH stable.

This tropical marine ornamental fish can eat frozen shrimp meat, tubifex, and marine pellets. Do not overfeed; excess may cause constipation, so feed once or twice daily. Check its condition often: look over the whole body each day for parasites, bacterial or fungal infection, or bite wounds, and watch its movement for anything unusual.