410 ILCS 620/21.4
"Catfish" means any species within the family Ictaluridae.
"Menu" means any form from which a customer is offered food and beverage, including, but not limited to, traditional printed listings, white boards, chalkboards, and buffet labels.
"Primarily engaged" means having sales of ready-to-eat food for immediate consumption comprising at least 51% of the total sales, excluding the sale of liquor.
"Restaurant" means any business that is primarily engaged in the sale of ready-to-eat food for immediate consumption.
"Similar fish" means species of fish similar to catfish, but within the families of Siluridae, Clariidae, and Pangasiidae.
If the Department of Public Health or a local health department receives 2 separate complaints for a restaurant that meet the requirements of this subsection, then the Department of Public Health or local health department shall inspect the menu, books, records, and inventory of the restaurant to determine whether, in the Department of Public Health's or local health department's discretion, the item advertised on the restaurant's menu is consistent with the books, records, and inventory of the restaurant.
The Department of Public Health or local health department shall impose a $1,000 fine upon a restaurant found to be in violation of this Section a second time.
For a restaurant found to be in violation of this Section a third or subsequent time, the Department of Public Health or local health department shall (1) impose a $5,000 fine, (2) suspend the restaurant's license, or (3) both.
If a restaurant's records indicate that it has purchased both catfish and similar fish from its suppliers and the restaurant labels an item on its menu as containing a similar fish, then the restaurant shall not be held liable for a violation of this Section.
410 ILCS 620/21.4