Officials hope London's waterways can one day be fully replenished
More than 700 fish are set to be released into rivers across London to replenish depleted rivers.
On Tuesday 250 chub and dace will be released at two sites, on the River Pool in Lewisham and River Ravensbourne in Bromley, both in south London.
Then on Wednesday some 500 tench and crucian carp will be set free in Canada Water, south-east London, to improve angling in the docks.
Numbers have been kept low to reduce competition so the fish will thrive.
Environment Agency fisheries officer Tom Cousins said: "We look for opportunities to improve the local fish stocks for the local anglers benefit.
"The River Ravensbourne catchment and Canada Water are prime examples of providing an amenity for local anglers while creating and enhancing the environment."
He added: "We know that the fish we have stocked in the past have always done well in these areas."
The species, which are considered well suited to London waterways, were bred at the Environment Agency's fish farm in Nottinghamshire.
The goal is to eventually bring naturally sustainable numbers of fish back to London.