to be extinct in britain is set to make a comeback. the tiny river fly, also known as scarce yellow sally, was thought to have died out in decades ago. but a small number were re discovered in the river dee in whales. and conservationists have made it there mission to bring them back through a special breeding programme at chester zoo. the insects were raised in aquariums that resembled conditions of the river bed involving managing oxygen levels, light and temperature. for more on this, i m joined byjoe chattell. he is an aquarium aquarist and assistant team manager at chester zoo. he led the breeding programmee for the tiny river fly. many of us may not have heard of the yellow sally stone fly, just talk is free what this little insect is. yes, they are an aquatic species and basically they have to sort of