Reverse flow UGFs are OK, though. Yes, marine tanks are harder to keep, but they are worth it. Filtration is a bit more tricky, protein skimmers are used. Luckily they aren't needed until after about 2 months. Crude must be cleaned out more often.
Food can be tricky.
I only use frozen shrimp and frozen brine shrimp. BUT, like I said, it is worth it. These are hardy little guys, and cheap too. After you've mastered the basics and have a cycled tank, wrasses are cool, so are tangs. I'd stay away from angels until you have more experience, and stay away from butterflys all together.