Jawfish - Yellowhead

Aquarium Requirements

Minimum Tank Size: 110 litres (30 US gallons)

Temperature: 24–27 °C (75–81 °F)

pH: 8.1–8.4

Specific Gravity (Salinity): 1.020–1.025

Alkalinity: 8–12 dKH

Ammonia & Nitrite: 0 ppm

Nitrate:< 10 ppm

Substrate and Aquascape:
A deep sand bed of fine aragonite (minimum 7–10 cm / 3–4 inches) is essential, ideally mixed with small shell rubble to support burrow construction. The Yellowhead Jawfish builds and maintains its burrow in sandy or rubble zones, using pieces of substrate to reinforce the walls. Provide open sandy areas combined with moderate rock structures for security.

Moderate water flow and excellent oxygenation are ideal. As a known jumper, a tight-fitting lid or mesh cover is mandatory to prevent escape.

Diet and Feeding

The Yellowhead Jawfish is carnivorous, feeding primarily on small planktonic crustaceans and zooplankton in the wild. In captivity, it adapts well to a varied diet of fine frozen and live foods.

Recommended Foods:

• Frozen mysis shrimp, enriched brine shrimp, finely chopped krill, and other small meaty foods

• Copepods and amphipods (excellent natural prey)

• High-quality marine carnivore pellets or micro-sized frozen blends

• Occasional live foods to encourage natural hunting behaviour

Feed 2–3 times daily in small portions, ensuring food reaches the fish near its burrow. The Yellowhead Jawfish may take time to become comfortable feeding in open water, so targeted feeding near the burrow is beneficial during acclimation.

Temperament and Compatibility

The Yellowhead Jawfish is peaceful and shy, spending much of its time near or inside its burrow. It is territorial toward conspecifics or similar jawfish, but otherwise non-aggressive toward other species. Once settled, it exhibits entertaining, watchful behaviour—often popping its head out to monitor its surroundings.

Suitable Tankmates:

• Peaceful reef fish such as gobies, firefish, clownfish, dartfish, and small wrasses

• Shrimp, snails, and other gentle invertebrates

Avoid:

• Large, boisterous, or aggressive species (e.g. triggers, large wrasses, or dottybacks)

• Other jawfish unless housed in a large system (at least 200+ litres / 55+ gallons) with multiple sand territories

Reef Compatibility

✅ Reef Safe

The Yellowhead Jawfish is completely reef safe, posing no threat to corals, clams, or other invertebrates. It may occasionally move small pieces of substrate or rubble while burrow-building, so ensure coral frags and loose decorations are secured.

Additional Information

Maximum Size: 10–12 cm (4–5 inches)

Lifespan: 5–7 years in captivity

Difficulty Level: Moderate (requires deep sand bed and secure cover)

Natural Behaviour: Burrow-dwelling, hovering, watchful, substrate-engineering

Origin: Western Atlantic – Caribbean Sea, Bahamas, Florida Keys

Colouration: Bright yellow head and upper body fading to pale blue-white posterior; translucent fins; males may exhibit slightly brighter colour during courtship

Summary

The Yellowhead Jawfish (Opistognathus aurifrons) is a captivating, peaceful reef fish celebrated for its vibrant coloration and intriguing burrow-building behaviour. With a deep sandy substrate, stable water parameters, and a secure, covered aquarium, it thrives and displays its natural behaviours beautifully. Ideal for aquarists seeking an engaging species that adds both motion and character to the lower regions of a reef aquarium.