Congrats on getting the new tank! That's a really nice one and it's a great size for a starter reef tank. Big enough to have plenty of system stability---and to be able to add cool fish and corals.
Definitely +1 on all fish can jump---and some will definitely jump. What's your reason for not wanting a lid? If it's because of the way it looks, there are some great solutions ranging from DIY cheap to expensive custom made options that look really nice. Regarding the latter, check out Clearview Lids and Kraken Reef for custom lid examples. Regarding the former, you can buy a cheap, thin acrylic sheet and cut it to size yourself or have a local glass shop do it for a few bucks.