Sorry, but I'm going to have to correct you on this. A well-fed Snowflake will not go after other fish, nor will they harm immobile invertebrates (corals, clams, feather dusters, etc.) They will go after motile invertebrates like shrimp, but they will leave pretty much everything else alone. The only issue with keeping a moray in a reef is the amount of waste they produce, and Snowflake eels produce only a miniscule amount compared with bigger fish like groupers or even other morays. That being said, you're spot-on about having a tight-fitting cover for the aquarium. You'd be surprised what size hole they can get out of.
Try to give him as varied a diet as possible; never stick to just one food source like silversides or shrimp. Mine have always received a diet of shrimp, fish, clam, squid and crab. You can feed them feeder fish on the end of tongs, but I would highly recommend against it due to the lack of nutrition in feeder fish. These eels take readily to prepared meaty foods, so feeding them live foods should never need to be an option.
