Short but sweet?...
I'm not sure this flash had enough length to it. A trip to the Zoo is an observation of longevity, and just as I was hoping the Zookeeper was onto a chalice of excitement, and an eruption of chaos with animals stampeding around the zoo with unintended malice and mania covered by the colourful joy of your artwork of choice.
Instead it ended, and in truth it transpires you may you have finished this for the difficulty experienced in constructing such a well animated and coloured flash, of in my opinion a unique style. I extend my reasoning for this in that most animation was inactive, slow or empty, and so forth was un exciting, and in result uncharming per se.
I assert that you should make an extension of this flash, and finish it with an implosion; by which I mean the Zookeeper could round up his animals all over again, in the same well animated, but more charming way. It should be at least twice as long if not threefold. If you can deliver this then I would be struck into amiability for this flash, as it has a lot of potential.
Approach a remake of this with patience, poise and willingness to add extra frames to each sequence, as a more lively scene such as with the fish morphation would add that coating of charm that this flash needs to reach the height it ought to be. So add layers of charm and a cherry top ending to this promising base, and you have a perfectly formed piece of entertainment.
7/10 4/10.