ARE FISH FUSSY EATERS?

We take a look at why fish prefer certain items of food

HAVE you ever stopped to wonder why fish eat some of the weird and wonderful baits that we present them? From so-called ‘naturals’, such as worms and maggots, to old faithfuls such as bread, to modern boilies and even artificial baits, why do fish fall for these carefully-crafted concoctions time and time again? The natural diet of coarse fish can vary substantially from venue to venue. Many scientific studies carried out all over the world have examined the diet of coarse fish and, generally, the conclusions have proven to be remarkably similar. Each species of coarse fish may have its favourite food but, as a general rule, the most abundant food will be the one that is eaten most often.

The ability to adapt

Roach are a good example of a species that are able to switch to whatever food is most abundant because they are omnivorous and do not specialise. Given a choice, roach will tend to feed on larger invertebrates, such as caddis fly larvae, water snails and freshwater shrimps. If these preferred prey are in short supply then roach can switch to feeding on smaller invertebrates, such as bloodworm. In times of famine roach will even bite off chunks of filamentous algae from the stems of reeds and water lilies. While the algae is mostly indigestible, they are able to gain some sustenance from tiny worms and insect larvae to be found among the plant material. While each species may have their favourite foods, in many fisheries they will be forced to try all kinds of different potential items because food is not abundant enough to prevent them from getting hungry. Fish have to be naturally curious and willing to test out anything that looks, smells or tastes like potential food, and this is probably why such a wide range of baits can prove effective. While fish can struggle to harvest enough food each day, this does not mean that they are eagerly searching for food all the time. Other factors, such as avoiding predators and resting can take up most of their days.

Locating food

A combination of different senses are used to locate potential food. Smell probably comes into play first as fish can detect tiny concentrations of some chemicals, allowing them to sense food from many metres away. The chemo receptors of coarse fish are able to register a wide range of different chemicals, many that we can also smell, but also amino acids (the building-blocks of proteins) and oils, which we cannot. As fish approach an area containing food, eyesight will become more important, enabling fish to pinpoint the source. Bright colours generally stand out well under water and, in an average depth river or pool, all colours can be seen well. Whites and pinks are especially visible, while dark greens and browns tend to blend in with the bottom. Finally, the sense of taste comes into play as the fish closely approach the food and take it into their mouths. Because fish have taste cells all over their bodies, but particularly on the barbules, fish can taste food before it actually enters the mouth. This is useful because it may enable fish to not waste time trying to consume something that is inedible. Other senses, such as the sense of vibration felt through the lateral line system – enabling pike to locate struggle prey, and perhaps hearing enabling fish to listen out for others crunching up snails – can also play a part.

While fish have very acute senses and can identify potential food quite easily, they must eventually bite the bullet and take it into their mouths to see if it is edible. Watching footage of fish feeding under water, it becomes clear that they are constantly taking in and spitting out all manner of different items, from bits of weed and detritus to natural food and bait. In fact, larger fish, such as carp, barbel, tench and bream tend to suck in mouthfuls of stuff at a time before dextrously sorting the edible bits and spitting out the waste.

Selecting what to eat

As a general rule, the richer the venue and the less numerous the fish, the more choosy they can be about what they eat. This can become particularly apparent with species such as tench that in well-stocked venues can be easy to catch on a wide range of baits, but in more sparsely populated lakes can be very difficult to tempt, with only baits such as maggots, casters and worms bringing bites. This can explain why on some venues novel baits are accepted straight away, while on others it may take a long time, if ever, for the fish to start eating the new bait. So-called ‘natural’ baits, such as maggots and worms are actually rarely encountered in the natural diet of coarse fish, but probably have the closest likeness to natural food. This explains why they are often accepted readily by wild fish. Not only do they bear a passing resemblance to natural food, but they also emit similar smells, have movement and are a similar size. Many baits give out a strong smell, especially boilies, pellets and pastes, which explains why they are able to attract fish into the swim and stimulate them to feed. Because they do not resemble natural food, fish that are less hungry may be disinclined to feed on these man-made baits even though they have been carefully formulated to catch fish. It might even be that the smell and taste of these baits is not instantly recognised as food.

Why do fake baits work?

Artificial baits often lack many of the sensory cues of natural baits. They do not move, have little smell or taste and are inedible, so why do fish still get caught on them? Colour and shape, perhaps resembling natural food, probably explains some of their effectiveness, but it is probably inquisitiveness that accounts for a big part of why so many fish are fooled by these artificial baits. After all, fish have no hands, so they have to suck a bait into their mouths to see if it is edible. So if you find yourself in the frustrating position of having a swim full of fish that steadfastly refuse to pick up your modern superbait then a change to a simpler offering that better matches the natural food of the fish can pay dividends. Fish can be incredibly easy or difficult to catch and the reason for this often comes down to just how hungry they are.

“Fish have to be naturally curious and willing to test any potential food”