The San Diego Zoo it certainly is not. But it is still a fun thing to see inside Inokashira Park. The animals are smaller and there aren't that many varieties, nor are there large numbers of any variety. The aviary has quite a few interesting varieties of winged critters, but that's about it. It's not a depressing zoo, but it really isn't worth going out of your way for, either.
Amazing park just a few minutes walk from the Park Exit of Kichijoji station. There is a zoo, paddleboats, and restaurants in the park. It's perfect for hanami, afternoon walks, a picnic, etc. There are usually performers and artists selling their wares on blankets around the center lake. And the shops and restaurants bordering the park are fantastic. Definite must-see.