The speartoothed grinner (Synodus sageneus) is a species of lizardfish that lives mainly in the Indo-West Pacific.

The speartoothed grinner is known to live in marine environment within a demersal range depth of about 12 – 30 meters.

The maximum length of the speartoothed grinner as a mature and unsexed male is about 26 centimeters or about 10.23 inches.

This species is native to the areas of Indo-West Pacific, Sri Lanka, the Arafura, Australia, and New Guinea.

It is recorded to be rare to find in its common environment of shallow shelf waters.