Marine Life of the Similan Islands - Frogfish

All of our staff have their passion for the sea. Today we look at one of Marcel's favorite marine life species in the Similan Islands: The Frogfish

One of the things I like best about diving is that you can be completely surrounded by amazing life. If you walk in the jungle or go on a safari, you might be lucky to catch a glimpse of a rare animal in the trees or far a way from you. But anyone who has made a dive knows how much life there is under water. Things might look boring when you are on the surface, but as soon as you put a mask on and pop your head under water, you find an amazing new world, rich in life. This is particularly true when you dive coral reefs. There are so many different species in such a small area and they come in all shapes, colors and sizes. Diving the Similan Islands is a truly remarkable spot. You can find anything here, from tiny Gobies to massive Manta Rays or Whale Sharks. I would like to introduce you to my top ten of favorite marine life that can be seen here.

On the first place comes the elusive Frogfish (family Antennariidae), also called Anglerfish. They have the amazing ability to get dive guides extremely excited when they find one. I have seen adult dive guides cheer like a child in his regulator. I remember a dive on Koh Tachai, where we found 2 Frogfish very well hidden deep in a piece of staghorn coral. All divemasters all got very excited, started to hug each other and slap each other on the shoulders. It took a bit longer for the customers to find out what got them so excited.

When you see a picture of a Frogfish, you might think "that's a nice fish, but why the excitement?". Well, the fact that they are so well camouflaged and so difficult to spot, make it a challenge for every dive guide to find one. And when do find one and take a closer look, you will find out that Frogfishes are amazing animals. They can sit motionless for a long time and are able to blend in completely with their surroundings. Sometimes they hide but even when one sits smack on top of a coral head, most divers will pass it without ever knowing. They often stay in the same place for months, but even when you know in which area it hangs out, they are always difficult to spot. And when you point one out to divers, it often takes a while before they realize that you are not pointing to a rock or piece of coral, but actually a fish.

Currently there are 45 species known in 12 genera. They vary in size between a few up to 30 centimeters. One very interesting fact is the way they catch their prey: The first dorsal spine is modified as a fishing lure to attract prey. The lure consists of the illicium (the spine) and the esca (the bait), and may resemble a worm, crustacean, or small fish. This lure is dangled, flicked and moved around in front of the Frogfish's head. If a fish wants to catch this make-believe prey it becomes prey itself - fast as lightning the Frogfish greatly expands its mouth thus creating suction pressure and engulfs the animal. This behavior is called aggressive mimicry. Frogfishes do not swim in the conventional way; instead, they "walk" on their pectoral fins or use 'jet propulsion' (forcefully expelling water from the small opercular opening generally behind and below the pectoral fins).

They are mostly bottom-dwelling fish, typically living amongst coral, at up to 100 meters (330 ft) depth, where they lie in wait for prey. They are able to change their color to match the background with high precision, and their camouflage is further aided by numerous warts and filaments on their skin, giving them an appearance similar to rough coral, a sponge or even a piece of drifting weed.

Typical dive sites in the Similan Islands to see one are Richelieu Rock, Koh Bon, Koh Tachai, Elephant Head, West of Eden, East of Eden and the Boonsung Wreck, but I am sure they hang out everywhere, the problem is just finding them.

So next time you are on a dive and all of a sudden your guide starts to get excited, gives a lot of funny hand signals and points at something that looks exactly like a piece of ordinary coral, chances are he has found you a Frogfish.

Check out this link: http://www.frogfish.ch/ to find more info on Frogfishes.

Next one: harlequin shrimps

-Similan Diving