Jacks Tornado, Richelieu Rock, February 2025

Hundreds of bigeye trevally (aka jacks) forming into a tornado at Richelieu Rock dive site in Thailand.

Jacks tornado, Richelieu Rock, Similan Islands, Thailand, February 2025 © chris@divehappy.com

Following on from the previous day’s barracuda tornado at Koh Tachai, at Richelieu Rock we were treated to a huge school of jacks doing the same.

Pook and the Jacks, Richelieu Rock, Similan Islands, Thailand, February 2025 © chris@divehappy.com

Things were a bit more challenging with the jacks than the barracuda. They were off the pinnacle out over the flat sandy bottom to the north of the rock, and much deeper, around 25 metres at the bottom of the school.

Jacks tornado, Richelieu Rock, Similan Islands, Thailand, February 2025 © chris@divehappy.com

It was unsurprisingly a bit more murky and green down underneath where the school was forming, but shooting upwards still got a good amount of sunlight coming in from the surface.

Jacks tornado, Richelieu Rock, Similan Islands, Thailand, February 2025 © chris@divehappy.com

The jacks were a lot more skittish than the barracuda, and so there were only a few moments when they started circling each other before the school broke apart again.

Jacks tornado, Richelieu Rock, Similan Islands, Thailand, February 2025 © chris@divehappy.com

The more unorganised jacks was a sharp contrast to the precise formations of the barracuda, but provided their own kind of chaotic beauty.

Jacks tornado, Richelieu Rock, Similan Islands, Thailand, February 2025 © chris@divehappy.com

It was pretty amazing to see such a massive amount of fish together – they are big fish, and the way the light reflected off their silver skin even at depth was magical. (My strobes certainly helped too).

Jacks tornado, Richelieu Rock, Similan Islands, Thailand, February 2025 © chris@divehappy.com

And after a couple of minutes, they dispersed, trailing back off into the blue leaving a big empty blue space behind.

Jacks tornado, Richelieu Rock, Similan Islands, Thailand, February 2025 © chris@divehappy.com

This was all part of an epic Similan liveaboard trip in February 2025 where we had an amazing run of luck – not just the jack tornado at Richelieu Rock and the barracuda tornado at Koh Tachai but an oceanic manta ray at Koh Bon, among all sorts of other cool stuff. See the full trip report.

Joy and the Jacks, Richelieu Rock, Similan Islands, Thailand, February 2025 © chris@divehappy.com