Crystal Palace Children's zoo closed around the year 2000. I think some local people who post reviews or photos of the Capel Manor farm online confuse the two, as they are located almost, but not quite, on the same site.
Much of the Children's zoo site was on land around the famous 1854 dinosaur park, which was subject to a £4 million refurbishment in 2002 to display the now listed dinosaur statues in a more sympathetic context (there are many photographs of the dinosaur park online in it's current refurbished state). As far as I know, there was some overlap between the old zoo and the dinosaur models. For example: prior to this, the tail of the giant sloth statue protruded into one of the goat enclosures on the verge of the lake). Now, the entire 'tidal lake' zone is separate from the children's farm slightly further up the hill. I'm unsure whether the earlier statue of 'Guy' the London zoo gorilla (the later one being the statue at London zoo itself) was within the old zoo boundary; if not, it would have been very near to it unless it was moved to it's current location.
The current facility at Crystal palace occupies a smaller section of land along the western strip of the park, and is essentially a city farm opened in 2008 by Capel Manor College as a teaching centre, although the farmyard is open to park visitors. Beyond the odd bearded dragon and pygmy hedgehog, this is a basic collection of tame UK domestic farm breeds, alpacas, and several varieties of domestic pet.
Some of the old zoo boundary fencing can still be seen running alongside the road to the stadium. One former enclosure remains but stands empty - one of the original fountain side pools, situated below the new college farm building and distinguishable by the old concrete bollards along it's edge, is filled with bullrushes now but used to house flamingos. There is still a metal plate map of the park at the lower entrance depicting a flamingo as an emblem of Crystal Palace Park.
This page, with a video at the bottom, is some of the best footage of the old zoo at Crystal Palace:
www.lararuffle.co.uk/history/crystal-palace-park-in-1986/
It held bigger and more unusual species during the 60s and 70s while they would have been more easily available/replaceable; by the 1990s it was mostly reduced to exotic birds, smaller monkeys and domestic stock. I never got to see the old zoo, but I've always wondered what they housed the infant forest elephant 'Jumbo II' in, during his short stay at Crystal Palace.