Monocentridae: G I A2

Monocentris japonicus (Houttuyn, 1782).

Pineapple fish

Egg diameter in µm

Number of oil globules

Diameter of oil globule in µm

Yolk texture

Perivitelline space

Position of oil globule at hatch

Gut length   at eye- pigment stage








61% of NL


Egg: The egg yolk is misty, has a strong circular segmentation, and from 5 to 20 oil globules, clustered together, usually light amber. On two occasions the egg was described as slippery. Incubation is 90-95 hours (22°C).

Larva: The newly hatched larva has an unusual pattern of pigment in the finfolds (B, B1 & B2). Eyes and mouth are undeveloped. The 4-day larva is shown in C. B: 1 day, C: 4 days, (22°C). The last image is a 4-day larva hatched from an egg collected in March 2010. A myomere count is not yet available for this larva.

No attempt was made to rear this larva. Two larval barcodes are currently available. Initially I thought this was Xiphias gladius, based on literature, but the barcode of a recently (2013) collected adult pineapple fish has provided a match (BOLD).

This egg is rare in the Park Rynie samples, and when seen, it is usually only one or two. No specific spawning time is apparent from the graphic (blue graph). They were not encountered in the DHM samples. The annual trend plot suggests they are less common now than during the first half of the study period (white graph). In the Park Rynie linked samples, the eggs were mostly taken offshore; hardly surprising, but the numbers are too low to be useful.

Linked samples