Given the following context:

Fishing season has begun and park ranger J. Audubon Woodlore goes out on the lake to check on the anglers. Humphrey the Bear is trying to catch some fish, but cannot seem to hold onto one once he catches it.  Woodlore sees the fish disappearing before his eyes, so he decides to stock the lake some more. As he heads to the fish hatchery, he sees Humphrey with a few fishing nets and rods, and asks him what he is doing.  When the bear tells him that he is going to catch some fish, Woodlore takes the rods and nets and tells him to "Go fish like a bear!" At the hatchery, Woodlore selects an envelope of fish eggs from a collection of eggs from such trout species as dolly vardens and rainbows. He fills a tub with water and inserts the eggs into it.  In a matter of seconds, several fishes pop up out of the water like plants out of soil.
When the ranger gets to the lake to dump the fish, he finds Humphrey in there, trying to eat one of the small fishes, which is then consumed by a much larger fish. Humphrey manages to remove the small fish from the mouth of the large fish, and then uses it to lure five other large fishes that jump out of the water, but then Woodlore appears to measure the fish, while at the same time punishing Humphrey by hitting him on the head, causing him to sink into the depths of the lake. When Humphrey grabs some more fish and emerges from the lake, he discovers a fish larger than any of the others; this turns out to be a fish balloon with which a young boy is playing. Humphrey pops the balloon, and both the boy and Woodlore kick the bear in the knee.

answer the following question:

What is the largest fish in the lake? 

a fish balloon