We anglers have a peculiar appreciation of bait colour. On the one hand, many anglers will buy maggots of mixed colours and ring the colour changes to keep catching fish; conversely, very few people use sweetcorn in anything but its natural yellow colour, and I’ve never encountered anyone who has attempted to colour bread flake!
Although fish eyes have form and function similar to humans’, there are significant differences. Being located on each side of their head, with wide fields of vision, fish eyes give them telescopic vision some distance in front of their heads. However, they also have a ‘blind spot’ in front of their mouths, effectively meaning that they don’t see their food just before they eat it.
Fish can differentiate one colour from another, albeit that this ability is less pronounced than our vision… a bit like watching a television with the colour control toned down. But it seems that they are able to see colours at the ends of the spectrum that are invisible to humans – at shorter (ultra-violet) and longer (infra-red) wavelengths. As light penetrates water, it is absorbed, with colours at the red end of the spectrum being absorbed first and blues last.
In clear and shallow water, changing bait colours makes sense, but in deeper and coloured water, many colours will appear black to fish. While it is certain that there is no single colour that is best for all fish in all circumstances, stand-out colours are often highly effective at catching the attention of passing or cruising fish… white, yellow and orange all seem to do this, probably because they contrast with the bed.
On the other hand, when fish become bait-shy, more muted coloured baits that almost blend in with the bed coloration may prevent fish being spooked by more visible offerings. There is huge room for experimentation with bait colours, using simple food dyes or powdered dye additives.
Fish eyes are good detectors of movement. Baits which sink slowly or are ‘twitched’ occasionally can produce instantaneous results, and neutrally-buoyant or pop-up baits are often highly attractive to fish because of their movement caused by the localised currents created when fish are in the vicinity.