Three feet is too narrow for all but the smallest bottom sharks and is way too narrow for any free-swimming sharks. Sharks that have to constantly change direction to swim will not fair too well in your planned tank. Smooth hounds will do fairly well but if you could add another foot or two would defintely help. The foot print of the set up is critical for long term care of a shark regardless of species. Too tight of a tank and the animal will never feel comfortable. As I have stated before anyone intending to keep sharks should do so with the intention of having them for their entire lives. If you approach shark keeping with this in mind you will have much better chances. Just a word of caution plan on having the best bio-filter and protein skimmer you can afford. Sharks are messy feeders and, here is the rub, they require the best water conditions possible. You are very wise to seek advice before you get a shark and I commend you for that. Please feel free to continue to ask questions and if there is any help I can give let me know.:thinking:
