Owen has declared that we must see the fish during every visit to the Columbus Zoo. He would stand at the glass watching the fish for hours if we would let him. Even when the zoo is busy, the aquarium offers a peaceful place to rest for a few minutes and cool down (summer visits) or warm up (fall/winter visits). Therefore, Ellen and I are generally happy to oblige Owen's request.
Since we live reasonably close to the zoo and have a membership, we visit the zoo several times each year and try to limit each visit to less than four hours. As such, we visit only a portion of the zoo and the aquarium during each visit. Fortunately, the aquarium is generally in the middle of the zoo, so we do not have to trek to the far reaches of the zoo to see the fish.