For as long as South African fly fishers have been obsessed with spotted grunter, misconceptions and heresies have spread about fishing for them and what grunter eat. Noticeably, and especially in the Western Cape, many grunter hunters have focused almost exclusively on one ubiquitous grunter food, the mud prawn. But has tunnel vision inadvertently done us out of options?

Yeah, maybe.

What grunter eat

I’ve noticed through many years of chasing grunter that, almost without exception, no two estuaries harbour grunter that feed and behave exactly the same. There is absolutely not a single fly that will catch grunter everywhere. My most successful pattern yet is not a mud prawn imitation, but a concoction meant to suggest any of three common and very different food sources in my favourite estuary. But then, without specific awareness and imitations of most of the things grunter eat around here, the fly would never have existed. In some cases you do have to get pretty specific if you want some hope of success.

There is absolutely not a single fly that will catch grunter everywhere.

With that in mind, here is a short list (in order of importance, roughly) of proven grunter foods. I include their scientific names because it makes it easier to search for good info on them. Some prey items still fly completely under the radar, while others have obviated their importance in the last two or three years. I hope you can grab some inspiration from these as we approach the second half of the grunter season. My advice is to keep it simple when designing your flies. It’s more important that your fly presents and functions well than for it to look exactly like the real deal.

My goal for grunter season ’22 is to simplify my grunter flies, and to whittle the selection down to as few patterns as possible. I’ll keep the menu below in mind, and for sanity’s sake, the fact that sometimes the fish bite, and sometimes they don’t.

Mud prawn

Mud Prawn LeRoy Botha

Upogebia africana is the most well-known grunter bait, probably the fish’s most important food, and therefore the focus of most fly tyers’ efforts. Wherever the estuary substrate is made up mostly of mud, these guys burrow. For reasons not fully understood, and at seemingly irregular intervals (except in the Eastern Cape), mud prawns up and migrate, making their way to new flats by swimming at or just under the surface.

Called the Prawn Walk, long exploited in the Eastern Cape, this behaviour in the Breede River and Kleinbrak gave rise to the Turd Burger and its derivatives. We also don’t fully understand why grunter continue eating at the surface, and hit big topwater lures for that matter, when there is no prawn walk evident. But they do, and we’re better for it. In my experience, surface-swimming mud prawn imitations are deadly in the above-mentioned rivers, and less so in other estuaries along the Garden Route.

Mud Prawn LeRoy Botha

The legendary JAM Fly was also conceived as a mud prawn imitation. It is the OG of grunter flies, used primarily as a sight-casting fly for tailing grunter. Tailing grunts on a mud flat are in fact blowing mud prawns out of their U-shaped burrows, a behaviour that you can take advantage of with JAM flies and other subsurface prawn imitations, as explained below.

Sand prawn

Sand Prawn LeRoy Botha

Callichirus kraussi and several closely related sand prawn species replace mud prawns over sandy substrates. Where grunter mostly focus on these things, be prepared to suffer.

The order of events when a grunter blows out mud prawns is something like this: Tail, blow. A huge mud cloud erupts from the burrow’s exit, along with its inhabitant. Locate, catch, eat, continue. All of this takes quite a few seconds and creates a lot of mud and noise. What’s more, the grunter must use his eyes, along with his other senses, to locate and catch the prawn.

Conversely, sand prawn burrows typically have only one entrance. The prawn must be sucked out, not blown. Now to some of you, no doubt, blowing and sucking are the same thing, but I assure you that in this case, they are not.

Sand Prawn LeRoy Botha

Adding to the trouble with the way a grunter hunts sand prawn is the fact that the water is generally clearer and shallower, which means that fish are always on high alert. So, the order of events when a grunter sucks sand prawns is as follows: tail, suck, bail. This takes roughly one and a half seconds, leaving very little time to present a fly to a fish that is not hunting by sight and that spooks at the slightest sign of danger. Sand is stirred up and ejected from the fish’s gills, but settles very quickly.

I have proposed before that it is possible that few grunters even know what sand prawns look like, given that they suck ‘em straight from burrow to gullet, and are located by sound and smell in the first place. Now, I have had some nibbles on sand prawn JAM flies, and so have others who have fished my imitations and their own. But whatever the truth is, good luck fishing to grunts on the sand. You’re gonna need it.

Marsh crab

Marsh Crab LeRoy Botha

Parasesarma catenatum is a small, dark crab, often found in great abundance in the vicinity of grass beds with compacted mud substrate that they can burrow into. It is a once overlooked food source, but in Knysna, footwork by guys like Luke Van Den Heever has shown that crabs are indispensable in Knysna. Luke ties a very effective brown Alphlexo for Knysna grunts. Whatever pattern you choose, keep it small and quite heavy.

Marsh crabs are a mottled grey-brown when small, turning to almost black dark brown when fully mature. They have fat claws that range in colour from creamy white through dirty yellow orange, to purple, although I don’t believe it necessary to even add claws to your imitations. A plain brown felt or brush-bodied crab pattern is fine. Fishing the fly static is the most common method, but keep in mind that marsh crabs can swim and run for their lives.

Marsh Crab LeRoy Botha

Grass Shrimp

Palaemon peringueyi and its close relatives are abundant in estuaries along the entire coastline, and yet not much is known about how grunter hunt them.

But, especially in places where grunts feed opportunistically, shrimps are a shoo-in; an obvious and highly available snack. May as well carry a few imitations like Kyle Reed’s Garden Route Spotted Shrimp or something like my Shawn pattern. You can lead sighted cruising fish with a twitch-pause retrieve, or even cast it at tailing grunter.

Cracker prawn

Cracker Shrimp Prawn Garth Wellman

Betaeus jucundus, aka the Cracker Prawn, Snapper Prawn, Kappertjie or Pistol Shrimp is dependent on mud- and sand prawn burrows. Although very common, is not quite as abundant as the other two. However, it is highly regarded as a bait for grunter. While sand prawns are also called crackers in some areas, these guys are the real deal. They often give their presence away by snapping their claws, emitting a loud crack that gives them their name.

Some believe that this sound plays a part in a grunter’s reaction to a rattle in a topwater lure, because rattles that emit a single, loud clack at a time are more effective than rattles with multiple moving parts. A simple olive JAM fly is a serviceable imitation of both mud prawns and crackers and I don’t believe a more specific imitation will make much of a difference. But, perhaps we should get cracking on a small enough rattle to include in the pattern.

Cracker Shrimp Prawn Garth Wellman
Cracker prawn photographs by Garth Wellman

Crown crab

what grunter eat
Crown crab photograph from

Hymenosoma orbicularum is a flat and round little crab with spidery legs. Slow and clumsy as they are, they prefer camouflage over running away. Their colour varies according to their environment, often matching the substrate perfectly. Therefore, not an easy one to spot, and not often mentioned by fly fishers. They are found over both mud and sand, where they dig themselves just under the substrate to hide from predators. Some are literally so chilled that algae grows on their backs. I’m fairly sure grunter eat them, especially when encountered on sand flats. On one particular sand flat that I frequent (whenever I feel like having my patience tested to the maximum) most of the few takes I’ve had were on small, pale crab patterns – far from any Marsh Crab habitat. Sand prawn imitations generally spook fish on this flat. So there’s that.


Prison Goby LeRoy Botha

what grunter eat

Caffrogobius multifasciatus, aka the Prison Goby, is one of the most common gobies in our estuaries. It is also one of those open secret grunter baits. I’ve barely tried tying imitations of them, mostly because I think the bait works for more reasons than the grunter simply hunting them by sight. Also, Prison Gobies prefer rocky habitats in estuaries – not a typical hunting ground for grunter. So, I believe there’s more to why a grunter would accept an easy meal like a smelly prison goby pinned on a bottom trace than actually meets the grunter’s eye. But then, for all I know I’m just missing out.

Moreover, there are gobies that do inhabit sandy flats, like the Knysna sand goby Psammogobius knysnaensis. I have no doubt that grunter will eat these, too. And that they may be very worth trying to imitate with a fly. Their posture and cryptic colouring won’t be easy to nail. But then neither is that of the mud prawn, and look where that got us.

Cape silversides and estuarine round herrings

what grunter eat

Gilchristella estuaria and Atherina breviceps get far too little attention from South African fly fishers. Not only are they in my opinion one of the very most important prey items for obligatory piscivores in our estuaries (more so in some cases than mullet), but I have seen grunter snacking on them, too. One day in the Touw river, I saw a baitball being herded and picked off in open, crystal-clear water about 1,5m deep. I assumed that the predators were leerfish, but closer inspection revealed them to be grunter.

Did I catch one? Well, that’s where it all falls apart, of course. But I know a few guys who have managed to cash in. Specific imitations have worked in Goukamma, and Clouser Minnows produce the odd accidental fish in Sedgefield. However, in Eastern Cape estuaries, Clousers tied in natural colours are sometimes the only thing that works. Although I’m not sure that has anything to do with eating silversides. Whatever fly you choose, try light olives and tans with some silver or green flash and keep it extra sparse. Although they are as unrelated as fish can be, silversides and round herrings look extremely similar. Translucent with the classic silver belly and lateral line.

Knysna seahorse

what grunter eat
Wikipedia’s pic of a Knysna Seahorse.

Finally, behold Hippocampus capensis. Only found in Keurbooms, Knysna and Sedgefield lagoons, this endangered endemic appears to play at least a small role in the grunter food chain. Not too long ago, an angler caught a Keurbooms grunt and kept it. While gutting the fish for the braai, more than twenty seahorses were found in its stomach.

The Knysna seahorse requires dense cover, notably provided by dwarf eelgrass and other aquatic weeds that form meadows in all three of its native estuaries. They also associate, when necessary, with man-made structures like underwater gabions that provide cover and something to anchor themselves to. They are at best a hack to imitate. But I’ve had a pattern in my pocket ever since hearing of that pony-sucking Keurbooms grunter. Perhaps I should finally go test the thing.

Bonus: Cape sole

Cape Sole LeRoy Botha

what grunter eat

There is no evidence that I know of that grunters eat Heteromycteris capensis. But the slurp-sized and obviously tasty juveniles Cape soles are abundant in the estuaries of the Garden Route and elsewhere. I encounter them often enough to say that I’d eat my hat if grunter don’t eat them. An imitation of these little guys may well be in order.

Of course there’s quite a bit more to the grunter menu. But I can’t think of much that you’d really want to imitate with a fly. We’ll leave well enough alone for now. Trust me on this.

Click here for Part 2 of Grunter Gotta Eat. I share some thoughts on how I’m simplifying my grunter fly box.

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