I don't see it on the zoo map. This is also why I make Kowalski and Doris meet at a beach, not in the zoo.

I'm guessing this:

They tore down the habitat, moved Doris to the ocean, and she happily lived by the shores of New York, where Kowalski will meet her in a later episode!..... unless....... she moves to Florida.... (There are SOOO many dolphins)..... but that wouldn't make any sense at all. xD

Doris.

They've got to have an aquarium. I wouldn't imagine the penguins could get out of the zoo unnoticed long enough for Kowalski to meet, fall for, go on a date with (I think), and lose Doris. Maybe they're hiding it underground! :D

Doris doesn't have to be in the zoo for them to meet!

Well They Put In The Series But I Never Been To The Zoo

Like I said in my post for "Do you think the penguins should travel more in the series?..."

DORIS IS PROBABLY FROM HOBOKEN. (the more you think about, it makes more sense, well to me anyway.)
I'm not repeating what I just wrote so...
link

Besides, on the entire zoo map, there is no aquarium shown.

err..... IDK!!!!!!