*Please note, this is the short version of the article, which excludes discussion around the Cottus revision, their migration history, and the reasons why they are surrounded with misinformation. The full version was published here , on CE Fish Essentials* The northern branch of Cottus perifretum from the River Wharfe, Yorkshire © max-pics, iNaturalist, 2024 For many years, the classification of the freshwater bullhead has been a topic of much confusion. So what species do we have in Britain, and how did they get here? Growing up along the river Avon, before I’d ever considered fishing with rod and line, as all young children should, I explored! I can recall many fond memories of walking along the margins with a little dip net, catching Three-Spined Stickleback, Minnows, and tadpoles; turning up stones in chalk streams, clutching Stone Loach and prickly Bullhead by hand; and even the using the age-old jam-jar-tied-to-string-with-a-chunk-of-bread-inside tec...