Basic profile of the caseless caddis larva this czech nymph is fantastic when fish are feeding hard on the riverbed. Czech nymphing was introduced to the UK in the 1990 World Championships. The Czech team beat the UK International teams on the Welsh River Dee. The Czechs caught fish in numbers from places that were thought impossibly fast or deep previously. This sent shockwaves through the world of competition angling. The technique is today considered to be pretty much a standard. Czech nymphs are heavier flies fished deeper that traditional fly fishing flies.