This is a pic from my classroom last year, when I had an ocean theme. This year I'll be doing a Zoo theme so I'll show pics of that when I start setting up my room next week.
I have 2 lines of fish because I teach morning and afternoon classes, so I differentiate the fish for each class. You may also be wondering how I do a line leader, door holder, or caboose. Well, I just have my line leader come up to the front and lead. Same with the door holder. The person whose fish is in front just becomes 3rd in line. It works great! No wondering where to stand or racing to the front. It works really well with my pre-k students because it also helps establish a routine and predictability with them is key! :)