Chief Brody now going through pre-teen years
Clearly Chief Brody is no longer a little fry, but he's also far from adulthood. He's entered the adventurous pre-teen years and has become much more comfortable in his surroundings.
It won't be long before the plant is gone. He uproots it at every opportunity. Anything that Chief Brody doesn't like, he now takes the initiative to change, including plant arrangements and the lay of the bedrock at the bottom of his tank.
His growth is really really apparent when you compare him to the Greek statue (above) and remember that it used to be bigger than he was as a small fry. This is something that often catches first-time Oscar keepers by surprise. They buy these cute little fish and put them in a small aquarium. Then two months later they wonder what they're going to do with this gigantic fish!