Nope, not normal. Test for ammonia & nitrites, nitrites will inhibit a fish's ability to process O2. If there isn't enough aeration, especially at a higher temperature, angels will go to the top.
Is there any air bubbles in the tank? Sometimes there simply isn't enough oxygen getting into the water for one reason or another and it might be worth adding an airstone. Another possibility is livebearers. If he/she lives with livebearers he/she will be hunting, although it doesn't sound like that from how you put it. One of mine spends a great deal of time tail down, nose up simply because that's where the fry hide. They are incredible hunters.
Hugs,
P.

, poor angel, would like to know what happened to it
/www.fishforums.net/index.php?showtopic=130498&hl=Hope that wasn't in this tank; http/www.fishforums.net/index.php?showtopic=130498&hl=
Angels are expensive feeders, & don't stand up well to aggressive n.w. cichlids.