The fire on 23 December started in the Animal Adventure area at 6am, leaving staff injured and closing the zoo.
Some 70 firefighters from four stations tackled the flames which left nine-year Misha the aardvark dead along with five meerkats.
London Ambulance said eight people were treated at the scene - six for smoke inhalation and two for minor injuries.
Mark Haben, zoological manager at Zoological Society of London (ZSL), said the fire had brought staff together and described it as being "very upsetting".
He said: "A couple of months in, it's still early days for us and we don't know the cause of the fire, so it's early days for us to speculate and there's still an ongoing investigation."
He was speaking with the upcoming breeding season starting, with more than 19,000 animals being counted for their inventory.
More than 750 species will be counted during the week-long stocktake including mammals, birds, reptiles, fish and invertebrates.
Mr Haben added: "The whole zoo has pulled together, the society pulled together and we're really gearing up for a successful 2018."
The zoo brought in 1.2 million visitors in 2016 and the arrival of a baby Okapi - similar to a giraffe - named after Meghan Markle will try to boost numbers further.