Javelin fish, or grunter, are a hard-fighting estuary and inshore fish that punch well above their weight. They are popular with northern Australian anglers because they eat well, pull strong on light gear, and often turn up in places you can reach from a boat or the bank.
In Australia they are mainly found across the tropical north, from northern Queensland through the Gulf and across the Top End into WA. They like muddy estuaries, tidal creeks, river mouths, flats and inshore coastal areas, usually around snaggy edges, drop-offs and deeper holes. Bigger fish also show up around harbour channels and nearshore rubble or reefy ground.
Javelin fish mostly feed on prawns, crabs, worms and small baitfish worked out of the mud and sand. They grub around the bottom and use the tide to move onto flats and along channel edges looking for an easy meal. When they are on, the bite can be sharp and solid, especially around a tide change.
Tide matters a lot with javelin fish, and they usually feed best on the making or falling tide when water is moving across flats, drains and channel edges. Low light helps, with dawn, dusk and overcast periods often getting them more active and less fussy in shallow water. Light to moderate wind can help by stirring up the water a bit, but strong wind makes small estuaries hard to fish properly and can shut the bite down. Smaller swell is generally better around inshore ground and river mouths, while bigger swell can dirty the water too much and make them harder to pin down.
A light to medium spin outfit with 10 to 20 lb braid and a fluorocarbon leader is a good all-round setup. Simple running sinker or paternoster rigs work well with fresh prawns, yabbies, squid strips and small fish baits, and soft plastics hopped slowly near the bottom can also do damage. Fish close to the bottom and keep your drag smooth because they hit hard then use the current.
Javelin fish get called grunter because they can make a distinct grunting sound when handled.