Monroe Timmy is an orange fish who has black eyes and a blue and yellow propeller cap, however sometimes he is seen without his hat. In some episodes, he appears to be green. He wears lime green pants with a black belt.
He does not like pistachio ice cream, but is shown that he asks for it, as seen in the episode, "Hocus Pocus."
He seems to enjoy SpongeBob's pain and agony during the episode, "Krabby Land," but near the end, he called SpongeBob, "Mr. SquarePants," a possible show of respect to SpongeBob himself. In the first movie, he is red with woman eyebrows and light green shorts.