Halimochirurgus spikefishes have a flat lower surface to the pelvis, the pelvis tapers to a point to the rear being much broader between the spines of the pelvic fins and at its rear, this feature places the genus in the subfamily Triacanthodinae. They have an extremely elongated snout, although the length of the snout is always less than the length of the remainder of the head. The mouth is not wider than the width of the snout immediately behind it and is not twisted to one side, The small, barely visible teeth are conical.
H. alcocki has a maximum published
standard length of while
H. centriscoides has a maximum published
total length of . ==Distribution and habitat==