I'm going to put a saltwater tank into my classroom. I have a couple of equipment options, going anywhere from a 4ft (72g) up to a 6ft tank of some time if I wish to purchase. I also have some smaller tanks.
I'd like some ideas on what you think would be the best type of tank for a high school classroom. Interest for the students, ease of maintenance (relative ease, mind you....I'm no idiot

), educational, etc. Hopefully this poll will generate some neat ideas.
Simply think back to your high school times (or current, maybe for our younger members) and let me know what you'd like to see in a classroom tank. Feel free to elaborate profusely below.
Thanks.