Lou is a shop clerk at the Barg'n Mart and a purveyor of other goods around Bikini Bottom. Lou is usually upbeat and treats his customers with respect. However, in the episode Party Pooper Pants Lou's personality departs from the norm, and we learn that he has changed from a happy fish (from a photo SpongeBob has) to a tired, sad fish because of SpongeBob's presence at the Barg'n Mart: "...but you have to leave right now!." In As Seen on TV a fish refers to Lou as "Vendor." We learn Lou's name in the episode Party Pooper Pants.
 Appearances in the Series
In Neptune's Spatula he tells King Neptune that SpongeBob pulled the Spatula out of the grease. In Ripped Pants, he does not like the joke that SpongeBob tells about the 'Banana Split' and 'Ripple'. In Life of Crime, he is a balloon vendor for National Free Balloon Day, in which SpongeBob and Patrick stole a balloon from it. In No Weenies Allowed he talks to Sandy about what ice cream is called in Texas. He is sometimes a cameo and has been seen in many other episodes. In The Sponge Who Could Fly, he teases SpongeBob and refutes that "they laughed at the guy who invented the light bulb too" at the Barg'n Mart. In the episode Sing a Song of Patrick, Lou sells torches to the angry mob. In The Two Faces of Squidward he squirts mustard on a fish's nose when handsome Squidward walks by.
Lou is a orange colored fish with a blue dorsal fin, blue arms and legs, and light blue lips. He wears a white paper hat, a white t-shirt, and a white apron that has pink ice cream stains on it. In Party Pooper Pants he wears a badge that says Hi!. In Porous Pockets he has a giant peanut sticking out of his hat. Lou's appearance has been inconsistent throughout the series. For example, in Ripped Pants he has lots of blue on his face and in Party Pooper Pants he does not have nostrils.
Lou has been voiced by at least 3 different actors.
- Lou always has the pink ice cream stains on his apron, because he sells ice cream, as seen on Ripped Pants possibly because he has multiple jobs. In Sandy, SpongeBob, and the Worm, he has ketchup stains.
- In Porous Pockets we learn that Lou has an ex-wife.
 Jobs he has/had
- Shopkeeper at Barg 'N' Mart
- Ice Cream Vendor
- Hot Dog Vendor at the Fry Cook Museum