Thresher shark — Alopias

The Thresher shark is a predator known for its extremely long, whip-like upper tail fin. This tail helps them stun schools of small fish during hunts.

You often see them in open water or near deep drop-offs. In places like Komodo or the Maldives, they appear at depths between 20 m and 50 m. I saw a group of three in 2018 while diving near Nusa Penida because the current was moving south.

Keep your buoyancy neutral. They are easily spooked by sudden movements or heavy bubbles. Do not chase them. Most divers miss them because they look for large shadows instead of watching the blue water for a thin, long line.