Sabertooth Fish Identification Guide

Key identification features

• Compact, deep-bodied, laterally compressed shape unlike the slender profile of most deep-sea predators
• Disproportionately large head and mouth relative to body size
• Extremely long, dagger-like fangs, proportionally the longest teeth of any fish; the largest lower fangs are so long they fit into sockets on either side of the brain when the mouth closes
• Dark brown to black coloration in adults
• Small eyes and a rough, bony skull with spiny ridges
• Adults reach only about 16 cm, while juveniles are smaller, pale orange, and more slender, once mistakenly classified as a separate species

Common look-alikes

• Sloane's viperfish: also has oversized fangs, but is slender and elongated rather than the sabertooth's short, deep, compact body.
• Juvenile versus adult sabertooth fish: juveniles are pale orange, thin-bodied, and smaller-toothed, while adults are dark, deep-bodied, and far more heavily fanged, making the two life stages easy to confuse with different species.
• Deep-sea scorpionfishes: share a large, spiny head, but lack the sabertooth's extreme, oversized fang teeth.

Where you'll see one

Sabertooth fish (fangtooth) occur in tropical and temperate oceans worldwide, living in the bathypelagic zone from roughly 500 down to 5,000 meters, making them among the deepest-dwelling fish species regularly encountered.