Bandit angels (known locally as "holos") have a reputation for being really hard to keep. Supposedly, they don't adjust well to captivity and refuse to eat.
However, my own experience hasn't reflected this. I had a very small (less than 2") bandit angel in my aquarium several months ago that I caught myself. Practically instantly, it was comfortable in the tank and was eating in less than a week. For the entire time I had it, it was eating well, looked comfortable, and got along great with the other fish. Unfortunately, it died in an ich outbreak that wiped out nearly all of my fish, so I can't say much about their long-term hardiness.
Also, a friend of mine often catches holos and makes sure they're eating before he ships them. Most of his fish have begun eating fairly quickly and reacted well to tank life.
IMO there are a few factors with holos that limit their suitability as aquarium fish, but they can do quite well if you're careful:
- Decompression. Holos are deepwater fish, generally found at more than 100'. Like many angelfish, they decompress poorly and will be injured if brought up too fast. A good collector will either bring the fish up slowly over several hours, or pin it underwater to vent the swim bladder. IMO the latter method is better for the fish. Unfortunately, there's no real way to know how your particular fish was treated.
- Size. Smaller fish respond better to decompression and acclimation. Holos larger than about 5" are unlikely to survive.
- Diet. Holos feed mostly on sponges in the wild, so a sponge-rich diet is a must. They'll eat other things in captivity but will probably require sponge-based angelfish food in the long run.
Holos are beautiful fish, and can be great pets if you get a healthy fish and can take care of it properly. Your best bet is to look for a small specimen and make sure it's eating well at the shop before you take it home.