What a fish sees underwater
The colour of a lure in the box and the colour of that same lure at depth are different colours. What changes them isn’t the lure but the water between it and the fish’s eye.
Water eats the spectrum in order
Long wavelengths are dampened faster than short ones. Red disappears first, followed by orange and yellow; the blue-green part travels deepest. In clear water a red lure stops being red within the first few metres — it turns grey, then black.
In murky water the order is different
Suspended particles and dissolved organics work the other way round: they dampen the short wavelength harder than the long one. So in turbid and tannin-stained water it’s yellow-green that travels farthest, and blue that disappears first. No single rule applies to every water here.
From below, it’s a silhouette, not a colour
A predator often attacks from below, and to it the lure is a dark shape against a bright surface. In that position, shade doesn’t register at all — only outline and size do. That’s why profile and body bulk decide more than the paint job.
Snell’s window
Because of refraction at the water-air boundary, everything above the surface is compressed for a fish into a cone of about 97 degrees overhead. Outside that cone, the surface acts as a mirror and reflects the bottom back. Hence the old advice not to stand against a bright background above the fish.
The eyes sit on the sides
In most fish the eyes sit apart on the sides of the head: the field of view is wide, almost all the way round, while the zone both eyes see at once is narrow and lies straight ahead. It’s into that zone that a predator brings its prey before the strike — the last metre, a lure passes right in front of its nose, not off to the side.
Fish do have colour vision
The retina of most freshwater fish contains cones — the cells responsible for telling colours apart. So the organ for it exists, and the question isn’t whether a fish sees colour, but how much colour reaches it through the water column.
Contrast instead of shade
The less light and the more turbidity, the more it’s the difference between lure and background that decides, not the colour itself. That’s exactly why extremes work in dirty water — black and acid brights — while delicate natural tones blend into the background and vanish. More on this in the card about water clarity.
What we don’t write here
We don’t give depths in metres at which each colour “disappears”. Those figures were measured in clear seawater, while clarity in our waters changes daily — carrying them over to a river would mean inventing a precision we don’t have.