That last factor is key to identification : body proportions . Under all its spines , tassels and fronds , the scorpion is a fairly conventional fish , with a stout body and blunt head . They are typically a mottled reddish brown , though those that favour reef rubble will appear in paler shades of white and grey . If you think there may be a scorpionfish in the area , look for an eye – to either side of the head you will find the biggest giveaway – broad pelvic fins ending in spines .
In the case of the stonefish , the pelvic fins are either hidden away or camouflaged to such an extent they may as well be invisible . Stonefish have a habit of half burying themselves in rubble once they find a promising spot , where they gradually mimic the colours and textures around them . Sometimes , all you see of their fins is a faint outline of a tail fin in the substrate , looking more like a fragment of shell .
If you ’ re looking for stonefish , you need to look for a more bulbous body and a large head with small eyes . In common with some scorpionfish , it has a downturned mouth , but with the stonefish this feature is grimly exaggerated . It looks up at the world with what looks like utter contempt , a cold , unlovable grimace .
In truth , finding a stonefish usually happens by chance , but once you ’ ve found it , it ’ s not going anywhere . Such is their trust in their camouflage and venomous spines , you can approach extremely close to view them or take photographs . Once they ’ ve chosen their spot and adapted their colouration to match the surroundings , they may stay rooted to the spot for several days .
Where you get clearly defined pectoral fins with the scorpionfish , the stonefish looks
Clockwise from top left : Devil Scorpionfish , Scorpaenopsis diabolus , Leaf scorpionfish Taenianotus triacanthus ; Spiny waspfish , Paracentropagan longispinis ; Spiny devilfish Inimicus didactylus
like a warty , frowning , slightly deflated rugby ball . Its pectoral fins are fleshy and formless , and its scaleless skin is covered in warts and growths of fuzzy weed . If threatened , it can display 14 sharp dorsal fin spines , each capable of deploying a potent venom , though it is only used in defence .
Defence mechanisms
If camouflage is the predatory superpower of these fish , then venom is their defensive coup-de-grace . Stonefishes have the most fully developed venom apparatus of all the Scorpaendindae , consisting of 14 dorsal spines , three anal fin spines and a pair of pelvic fin spines , all armed with venom glands .
As to the ‘ juice ’, stonefish venom is a mixture of proteins of high molecular weight . A compound called stonus-toxin has been isolated from the venom of the estuarine stonefish , Synacieia horrida , and has shown a unique molecular sequence . In lab experiments , stonus-toxin and the raw venom have both caused a rapid reduction in blood pressure , potentially sufficient to kill those with weak hearts .
Here ’ s the horrific bit . The immediate effect of a stonefish sting is severe burning pain , which does not go away for days . Blisters develop at the puncture site , which becomes the centre for extensive inflammation . Other symptoms
This Red Sea stonefish , Synanceia nana has recently moved to a coral head ; it still bears the algae and textures of its previous background
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