How much time would you recommend for a trip to Beijing Zoo?

If you are pressed for time, 2-3 hours is enough to cover all the main attractions. 20 mins for he panda house, 30 mins for the aquarium, and 50 mins for the other animals in the zoo, the rest of time is for the walking and ferry ride.

It depends. Are you a person who likes to stand and watch the animals for a while at each display? or do you see it, take a picture, and keep moving? If you want to spend time with ALL of the animals, you'll need the whole day. If you just want to see the giant pandas and glance at the others, 2 or 3 hours for the main zoo, plus extra time for the aquarium. I do recommend spedning a bit of time with the bears and with the red pandas which are next to the bears (the map is old).