The new purpose-made lake covers eight acres at Tuckey Farm in East Claydon Road, and comes complete with landscaping, fishing platforms, a clubhouse and parking.
Anglers can view facilities, enjoy a lamb barbecue, and talk to a carp expert at the open morning at the new members-only catch-and-release lake.
Richard Haynes, from Tuckey Farm, said: "The lake has been so well designed that you can't see the edges at any point. It has been stocked with common and mirror carp and has already proved to be of enormous benefit to wildlife, encouraging many species to the farm.
"We have ducks, geese, coots, waders, dragonflies and damselflies. The marginal plants we put in are doing well too."
Mr Haynes, who is Berks, Bucks and Oxon NFU chairman, added: "This project has not been grant aided - it is a diversification to generate extra income for the farm in a sustainable manner.
"A limited number of fishermen are invited to become members and they will be able to enjoy fishing all year round, day and night."
Native trees planted on the site include oak, ash, alder, field maple, hazel and beech.
The project is a diversification for beef, sheep and arable farmers Mr Haynes and his parents, Barry and Bridget Haynes.
An oak was planted beside the fishing lake car-park last week by NFU president Peter Kendall to mark the centenary of the NFU, which should still be growing at the next centenary.
The open morning runs from 10am to noon.