The saying 'use a big bait to catch a big fish' is generally attributed to carp bait pioneer Fred Wilton. Now while there is more than a grain of truth in this, there are many times when large baits will not score. For the most part, even large fish fed upon quite small prey and it is only when pre-baiting occurs that their behaviour is modified to readily accept larger baits. Most species of coarse fish can feed on a whole variety of different kinds of food. This is a great advantage over other, more specialised families of fish, allowing them to colonise a wide range of different environments. Bream, tench, carp, roach and rudd can feed on tiny prey even as adults, by making use of a remarkable adaptation of the gills. Inside the fleshy gill arches, used for breathing, lies a system of bony gill arches, which form a finely divided sieve. These are particularly well developed in bream, which are able to feed on tiny zooplankton by filtering through the gill arches. This feeding mode is thought to be particularly useful when the water temperature is very warm and bream can be seen just below the surface and appear to be breathing heavily. They are not fighting for breath as some people believe, but are instead feeding on the dense clouds of daphnia that gather just below the surface. When bottom feeding, bream tend to feed on chironomids that can be found in the top few centimetres of mud. To sort these small animals from the mud, the bream sucks up mouthfuls of the lake bed and passes it through the sieve. The mud is then passed out through the gills. This is a very efficient system in bream, less so in the less specialised roach, which enables lakes to support high densities of bream. The continual turning over of the lake bed often leads to the characteristic coloured water when bream are feeding heavily. Although chironomids are extremely abundant in many lakes, a large population of bream can have a significant impact on both water quality and the numbers of chironomids present. This can be a problem as emerging chironomids are also the main food of many species of water birds. Now, although living in a shoal gives the fish more confidence, it means that they will quickly deplete the amount of natural food in a swim. When the amount of food falls the bream are forced to move on to feed. This is how all herd animals must feed, and many also follow the same patterns day after day. By the following day, the amount of food in the feeding spots will have increased again. Although it is difficult to judge, I believe that the bream actually do not have a long term impact on the spots they feed upon. By the next day more invertebrates will have hatched and be available. Also, when threatened with attack, many invertebrates will also withdraw into the relative safety of the silt. So each day the shoal of bream follows the same course around the fishery picking up food as it goes. How much can a shoal of bream consume in a day? If we make a few rough assumptions then I think we can get some idea of the effect a shoal of bream has on a water. Let's assume the bream average ten pounds in weight and that there are fifty of them in a shoal. Now, in the summer months, each bream will eat around five percent of its' body weight each day. That gives a grand total of twenty five pounds of invertebrates each day, quite a considerable amount. On many of the waters I fish, which have very little angling pressure, natural small baits are most certainly the best. Matching your bait as closely as possible to the natural prey of the fish also helps. Rather than being put off by the idea that my bait is a 'needle in a haystack', I am encouraged by it, as the fish will eat the whole haystack and still come back for more!