Biodiversity #17 – Porcupinefish (Diodontidae). Any other day of the week, they look like the picture above. But on bad hair days … like the pufferfish, the porcupine fish has the ability to inflate itself, thereby making it bigger and rounder and harder to eat, yet retaining its ability to swim – albeit upside-down! Second defence mechanism is provided by sharp spines which radiate outward when inflated. And finally, as if that’s not enough: highly toxic to anything that eats it – including man.
BTW – this is not my photo: I would not, by choice, stress a fish sufficiently to get this reaction. (Though it occasionally happens with my buddy).