These masters of disguise and trickery assimilate into their surroundings, complete with matching features, even if they are found in the most conspicuous places on the reef.
They either blend in or have bright warning colours that send signals to would-be-predators that they are poisonous and definitely distasteful.
These are the Scorpionfish, one of the world's most venomous fish. They are born with fins but they don't really swim, so these fish spring forward to ambush prey.
While searching for this group of bizarre and awesome predators around South East Asia, knowing the reef helps especially in identifying things that don't belong there. These fish lurk on the rocks, crevices and reef tops. In some places in Indonesia, they lurk in volcanic sand, half buried.
When I tell my dive buddies that we will be looking for toxic predators, they give me strange looks. But having an objective prior to dives allows buddies to keep a lookout for your subject no matter how bleak the prospects of seeing anything may seem.
Whereas combing the reef without an objective might cause one to miss the nicely camouflaged Scorpionfish amongst the cluster of tunicate or sponges. But having trained my vision, picking out their unmistakable shapes have become second nature.
The still, silent predator is armed and ready, with toxin in its spines, and its an obvious precaution for us to steer clear. Approaching it from the side or front allows the fish to accept our presence, otherwise they will dart away.
Hovering above or beside my quarry without touching the reef is a skill of buoyancy-control that involves regulating my breathing pattern. But it gets harder to stay steady when my heart is palpitating with excitement as I frame the deadly fish in my camera's viewfinder.
Not all vibrantly coloured fish are pleasing to the eyes. There is a species closer to the Stonefish family that looks monstrous, the kind that would inspire Hollywood's production of alien movies.
It's called the Devilfish (Inimicus didactylus), complete with dorsal javelins in place of fins; pelvic fins that have evolved into a two-pronged garden rake (used for locomotion on the seabed) and a skeletal face that exudes total evil, if a fish were possible of such emotions.
If it wasn't for its smallish size of 20 - 26cm, it would have been an even more harrowing experience seeing something so horrific emerging from the sand midway in my dive. Found burrowed in sandy sea beds, the Devil Scorpionfish is well camouflaged with only its eyes and mouth exposed on the sand's surface.
The dorsal spikes are tucked down as it lies completely still, in wait of a passing juicy morsel to ambush. The inner pectoral fins are brightly coloured and though this species may look mottled and knobbly, it is a creator's masterpiece. It's also splashed with patches of distinctive colours on its body, a trait which gives away its presence on the volcanic sands of the Lembeh Straits in Northern Sulawesi, one of the places I've chosen to look for these bizarre creatures.
Closer to home, this fish also lie in wait in the sands of Tenggol Island, Terengganu. But upon discovering its hiding place in one of my dives there, it chooses to walk away from the glaring video light of my camera!
Splashed with mottled patches of colour on its body, the Devilfish would much rather have feet any day. Very little is known about the dangers of this hidden monster. However, having pictures to caution other divers from putting their hands indiscriminately on the reef helps prevent a nasty wound and a holiday cut short for a trip to the emergency room.
I have combed the reefs in Mabul (Sabah), Tenggol, Bali and the sandy sea bottoms at the Lembeh Straits to capture these stunning fish over the years. I discover other toxic creatures along the way and have learnt to capture them on video to show you what people seldom see. In my next article about the Ocean's Predators, the octopi makes a debut!
Pamela Lim writes travel stories, teaches scuba diving, cycles, organises trips and indulges in photographing birds. More at www.pummkin.net
If you are stung
If you are stung
As best as possible, avoid getting stung. But the Scorpionfish is so cryptic in its environment that it's hard to see. The chances of accidentally brushing over it are higher if you like to hover near the reef.
If you are stung, get out of the water immediately and seek help. The sooner you get treatment, the better your chances of recovery. Soak your wound in hot water (45° C) - as hot as you can tolerate, but not boiling water.
How well you do depends upon how much venom has entered your body and how soon you get treated. Hot water deactivates the poison but if there are signs of intoxication, nausea, feelings of weakness, shortness of breath or if you become unconscious, seek immediate advanced medical care. Buried: A Devil Scorpionfish (Inimicus didactylus) lurks halfcovered in the sandy sea bed. Buried: A Devil Scorpionfish (Inimicus didactylus) lurks halfcovered in the sandy sea bed.
The stings of other species in the family like the Stonefish can be fatal.
The best rule to apply when diving in search of cryptic predators is: Do not touch anything and keep clear from the reef. Wear a thicker wetsuit, as it will provide some protection from accidental brushes with stings.
Engage a proficient dive guide of the area to give you an orientation of the site before you venture off with your buddy on subsequent dives. They provide invaluable resources to help you get acquainted with the underwater environment - they also know where the resident Scorpionfish, octopi or sharks are!
Be neutrally buoyant to avoid crashing into the reef. Any aggression from animals is defensive. As long as you stay in practice and dive responsibly, you should not encounter any incidents.