What critters can I get?
 

I have a 100 gallon reef only tank that has been setup for 4 months. I have a mix of polyps and lps corals as well as a few cerith and astrea snails and red and blue-legged hermit crabs. I'm trying to keep the tank low maintenance since I am not around enough to monitor it all the time. I don't trust my family with the responsibility of feeding the tank on a regular schedule, and god forbid, if one fish should die, it will raise the ammonia and possibly kill others. Although I would really like to get some fishes, I just don't want to risk it without my constant supervision. On the plus side, I don't have to worry about fish waste. So I was wondering what other critters can I get to add some life to the tank with the following conditions:

1. Maybe some feeding, but not daily feeding.
2. Wouldn't adversely affect the water quality should it die?
3. Hardy.

Thanks!

I think emerald crabs, sally lightfoot crabs, pom pom crabs, cleaner shrimp, fire shrimp, Sexy anemone shrimp, porcelain crab, spider decorator crab, arrow crab, various star fish, or a sea hare make interesting creatures to observe. I would say all of those fit your criteria. I am sure there are hundreds of options, those are just a few that come to my mind. For what it is worth, I would not sweat putting a few small fish in the tank. If a small fish died and you did not catch it for a week, it would not crash your tank in my opinion. Particularly not if you have a decent number of crabs who would gladly eat the fish for you.

Some shrimps will add some movement or perhaps a starfish or two. Beyond that I don't know what to recommend.

Let us know what you decide.

Jab beat me to the punch, but a small fish or two shouldn't be an issue. Since you're not interested in many fish you could get a damsel, they can't be killed!

cleaner shrimp and peppermint shrimp I'll suggest.
arrow crab is a good cleaner but too aggressive, growing fast and predator for small fish.

some kind of goby. IMO very low maintence.

Thanks. The reason i'm weary about fishes is because i had a devastating incident a few years ago. My ocellaris clownfish had a disease and died. It was trapped in the back of my live rocks where it was hard to reach. I saw snails feeding on it so I left it alone. After a few days, the water started to get murky. At that point, I did a number of water changes, but it was too late. Other fishes started to die as well as snails and crabs, followed by corals. A few days later, the whole tank crashed. This was my 29 gallon.

If that is your tank for your avatar... a fridmani psuedochromis would be awesome in it. maybe one of those and a gobie. If still no fish... I say, get a cleaner shrimp. They are very active... especially at night, going hunting for pods. Plus you can have the kids wash their hands real good and then stick them in the tank and the shrimp will clean them. Get two and they will spawn.