Zusammenfassung: The feeding habits of C.taenia were studied by means of monthly samples taken over a 2-year period, October 1972-October 1974, from two sites, one on the River Great Ouse at Newport Pagnell and the other at some neighbouring gravel pits. Dietary components, seasonal variation in these components, and seasonal and diurnal variation in feeding intensity were examined. The ecological niche of the food items and their size range are discussed, since both these factors appeared important in governing the microhabitat of the fish. The feeding activity followed a seasonal cycle with little or no feeding in the winter and a high level of feeding activity in mid-summer. The diet showed a predominance of small food items, such as chydorids, copepods and rhizopods. These items varied in occurrence during the feeding period which appeared to be related to their own abundance, pointing to non-selective feeding by the fish. The small size and benthic habits of the food items, many of which are closely associated with surface layers of mud and weed, indicated a preference by C.taenia (L.) for feeding in this type of habitat and on this type of food, in contrast to the stone loach, Noemacheilus barbatulus (L.), which is believed to inhabit stony areas and take larger food items.

Zusammenfassung: A laboratory study of female G. aculeatus revealed no conclusive evicence of active female mate choice on the basis of male aggression levels. However, highly aggressive males failed in 95% of all choice tests. The less aggressive ´chosen´ males where generally successful again in subsequent trials with the same female, and certain males were consistently successful with different females. Females exhibited an increased readiness to spawn at the end of the reproductive season, although the same males were usually selected again.