Opistognathus castelnaui

Opistognathus castelnaui, commonly known as Castelnau’s jawfish, is a large jawfish. Their base colour is yellowish to greenish with a brownish reticulated pattern on it and a series of dark spots along the base of the dorsal fin. Dominant males show a high degree of red, especially on the head.

Despite being very beautiful, attention must be paid to the fact that they grow quite large, and with that large mouth small fishes and shrimps may not be the best combination.

These fish are usually found on open sand and rubble substrates in a little deeper waters. They can best be kept alone or as a proven pair. They make burrows in the sand which they cover every night and rebuild the opening in the morning. It’s best to provide them with multiple grain sizes of sand and maybe some coarse coral rubble, so they can make a good burrow.

They feed mainly on zooplankton when small and can best be fed with live and frozen food like copepods, artemia and small gammarus, but usually will learn to feed on high quality flakes and pellets as well. As they grow larger, larger food can be given, although they’ve no problem sifting small food particles from the sand.