# Bill Lewis Gnat: the 3.8 cm micro squarebill that actually casts > A 3.8 cm / 1.5 in squarebill weighing 3.5 g / 1/8 oz and running to 1.2 m. Weight transfer, BFS tackle, retrieves and colors for perch, trout and bass. - Source : https://carnafish.com/en/leurres/bill-lewis-gnat-tiny-squarebill-crank-1-8oz/ - Language : en-US - Updated : 2026-09-16 ## Spec sheet - Brand : Bill Lewis - Model : Gnat Tiny Squarebill Crank 1/8oz - Type : Micro squarebill crankbait - Target species : Bass, Perch, Trout - Size : 3.8 cm / 1.5 in - Weight : 3.5 g / 1/8 oz - Running depth : 0.9-1.2 m (3-4 ft) - Retrieve speed : medium, with a short pause after every deflection - Action : wide wobble for the size, square bill that kicks off hard cover sharply - Rigging : straight to 20-25 lb fluorocarbon, a small snap or a loop knot, stock pair of small trebles - Colors : chartreuse with a red back in stained water, brown craw over rock, translucent roach in clear water Some days the fish are right there, visible and active along the edge — and they refuse anything over 5 cm. Hard-pressed small ponds, low clear rivers in late summer, harbours and basins everyone walks past: perch follow, turn, and leave. In those conditions, dropping down in size is often the only variable that genuinely changes anything, and a micro-crankbait like the Gnat stops being a novelty and becomes a real tool. ## 3.8 cm, 3.5 g, and a 1.2 m running depth The numbers are straightforward: the Gnat measures 1.5 in, or 3.8 cm, and weighs 1/8 oz, around 3.5 g. Bill Lewis state a 3-4 ft running range, which is 0.9-1.2 m. That's exactly the layer where most shallow edge fishing happens: the top of a break, the crown of a rock pile, a lily pad edge, the first few metres of a gravel beach. A crankbait this size immediately raises the problem the rest of this page tries to solve: 3.5 g is not much. Not much to cast with, not much to hold depth with as soon as there's wind or current, not much to feel anything through. The Gnat answers the first point with an internal weight transfer system — a ball that slides back in the body during the cast to stabilise the flight, then returns to its running position on landing. On a lure this light that isn't a gimmick: it's the difference between a cast that tumbles at six metres and a clean one at fifteen. ## A square bill, and why that matters at this size The square bill isn't styling. Its job is deflection: when it hits a rock, a branch or a piling, the lure kicks violently sideways instead of hanging up, and that sudden break in trajectory is the number one bite trigger on a crankbait. Most micro-cranks on the market use a round or oval bill designed for a smooth run and depth; they snag more and never produce that break. In practice that means the Gnat is a contact lure, not an open-water one. You work it against something hard: riprap, a slab, deadwood, the wall of a basin. The ideal retrieve is a steady medium pace, interrupted by a very short pause — half a second — every time the bill ticks something. The bite almost always lands in the second that follows contact. > On a micro-crankbait, resist the urge to slow down when nothing is biting. At 3.5 g, slowing down lifts the lure out of its running layer and off the spot entirely. If you have to change something, change the casting angle so the bill contacts earlier in the retrieve, not the speed. ## Tackle is the real subject here This is where most anglers get it wrong. A 3.5 g lure will not cast properly on a setup built for 10 g, however good the caster is. ### On spinning A light rod of 1.80-2.10 m rated 2-8 g, with a tip soft enough to load on the cast. Thin braid of 0.06-0.08 mm and a 20-25 lb fluorocarbon leader. The fluorocarbon has a mechanical role here as much as a stealth one: it sinks slightly and helps the lure hold its depth, where a floating mono pulls it up. ### On BFS This is the format BFS exists for. A casting BFS setup, with a lightened spool and a well-tuned magnetic brake, transforms the fishing entirely: accurate casts under branches, thumb control of the lure, instant pickup after the splashdown. If you regularly fish under 5 g, that's the single purchase that changes the most. ### The classic mistake Clipping on an oversized snap. On a 3.8 cm lure, a standard 20 kg snap is meaningful mass right at the front — it weighs the nose down, chokes the bill and kills the wobble amplitude. If you want a quick connection, use the smallest snap you can find; otherwise a loop knot in the fluorocarbon does the job perfectly and leaves the lure free. ## Three species, three ways to use it Bill Lewis name bass, panfish and trout explicitly. Transposed to Europe, that means three distinct styles of fishing. For **perch**, the Gnat fishes on a fast straight retrieve along riprap and pontoons, hunting hard contact. Perch shoals react to deflection and often follow several at a time, which lets you string bites together on one spot. For **trout** in rivers, cast upstream and retrieve slightly faster than the flow. The 0.9-1.2 m range covers most medium river pools, and the small profile slips in where a 6 cm lure empties the swim. For **bass**, it's a pressure lure: heavily fished waters, educated fish, late summer. It doesn't replace a full-size squarebill like the [6th Sense Crush Mini 25X](https://carnafish.com/en/leurres/6th-sense-crush-mini-25x-crankbaits/), but it takes over when fish stop accepting the usual volume. ## Colors by conditions - **Stained water or overcast skies**: the chartreuse-and-red-back of the photo, a hard contrast that stays readable as visibility drops. - **Rocky bottom, lightly colored water**: a brown craw finish, which matches what perch and bass are actually eating on that substrate. - **Clear water and bright light**: a translucent roach or natural silver, worth switching to as soon as fish follow without committing. ## When size is the only variable left A micro-crankbait doesn't rescue a session that was wrong from the start. But once you've already checked depth, speed and spot type and the follows still produce no bites, dropping to 3.8 cm is often the last useful variable. For the sessions where this format runs out of road — wind, current, a need to cover water — go back to a [Bill Lewis Hammer Flat Crank](https://carnafish.com/en/leurres/bill-lewis-hammer-flat-crank/) or a [Rapala Ultra Light Crank](https://carnafish.com/en/leurres/rapala-ultra-light-crank/), still light but far easier to propel. Knowing whether the water in front of you calls for a micro-crank or a search bait is exactly the kind of reading [CarnaFish](https://carnafish.com/en/) sets out to make accessible: photograph the spot and the AI hands you the zone, the depth and the lure family that fit the conditions. To go deeper into perch-specific spots and retrieves, our [guide to lure fishing for perch](https://carnafish.com/en/blog/peche-perche-leurre/) covers the situations where this format genuinely earns its place. ## The short version - 3.8 cm for 3.5 g running 0.9-1.2 m: a shallow edge lure, not a water-covering one. - The internal weight transfer is what makes the cast usable at this weight; without it the format would be unfishable on standard spinning gear. - The square bill needs hard contact — rock, wood, concrete. In open water the lure loses most of its point. - A small snap or a loop knot is mandatory: a heavy connection chokes a lure of this size. ## FAQ ### Does the Gnat really cast well for its weight? Better than most 3.5 g lures, thanks to the internal weight transfer system. Still expect modest distances next to a 10 g crankbait: the Gnat's value is short-range accuracy, not outright range. ### Do I need a BFS setup to fish it? No, a light 2-8 g spinning rod with thin braid handles it fine. A BFS setup mainly buys accuracy and better control under cover, which matters if you fish this class of lure often. ### How deep does the Gnat actually run? Bill Lewis state 3-4 ft, roughly 0.9-1.2 m. In practice the real depth depends heavily on line diameter and speed: a thick leader or a slow retrieve will keep it running higher. ### Is it any good for river trout? Yes, it's one of its most natural uses. Cast upstream and retrieved slightly faster than the current, it covers the water column of medium pools and stays discreet enough not to empty the swim on the first cast. ### Can I fish it in weed? Not really. Even with a square bill, two trebles on a 3.8 cm body collect vegetation as soon as it gets slightly dense. Keep it for hard bottom, riprap and clean edges. ### Should I upgrade the stock hooks? Rarely worth it. On a lure this light, fitting bigger trebles unbalances the run and costs the lure part of its wobble. If you do swap them, stay strictly to the same size and weight. --- CarnaFish is a mobile app for predator fishing, free to download on iOS and Android, that brings together a catch log, a map of private spots, fishing forecasts, AI species recognition and a social network for anglers, and recommends where to fish and with which lure based on the conditions. To cite this content, mention “CarnaFish — carnafish.com” and link the source page.