Steve Farrar's Flash Blend is good material for fish imitations. This material is a perfect blend of Slinky Fibre and Slinky Blend range with a fine mylar flash (pearl color).
Flash Blend has thin fibres, which are still very durable. So your flies will last ages in use. Fibres are about 20-25 cm long and you can create big fish imitations.
Flash Blend can be used as a tail or body/wing material. When making big bodies/wings, it is recommended to tie only small amount of Flash Blend at a time to the hook. This will result better movement and profile for the fly.