Tough as old boots. This is a fish that feels like sandpaper. Its skin is rough and grating, which is exactly what the Māori names Hiriri and Kookiri describe. Run a finger along it and the reason becomes clear. This is not a fish that apologises for its appearance. A sharp spine on its back locks into place when threatened. It is a defence mechanism that makes predators think twice. It can also change colour. It shifts from grey to green to brown to blend in with its surroundings. The fish is rough and ready. Despite the unappealing exterior, something wonderful hides inside. The flesh is sweet and white. It is so good that people gave it an alternative name: creamfish. But getting to that flesh requires wrestling with that sandpaper skin. Most people cannot be bothered. The leatherjacket swims through rocky reefs, harbours and estuaries. It is largely ignored. It is a common resident of shallow waters down to 50 metres. It browses rather than hunts. It picks small crustaceans, worms and algae off rocky surfaces with its small mouth. It crushes shells with surprisingly strong teeth. It is not targeted by commercial or recreational fishers. It is not worth the effort. But it turns up occasionally as bycatch in set nets and rock lobster pots. It is an accidental visitor to the deck. In Māori tradition, the tough skin had a use. People sometimes employed it as natural sandpaper for smoothing wood. The fish that feels like sandpaper becomes sandpaper. That is efficiency. The rocky reef is shallow. The leatherjacket browses, rough skin sandpapery, changing colour to match the rocks. The net sweeps. The leatherjacket is caught. It is thrown back. It does not know it is sandpaper. It just wants to eat algae.