I had a snowflake Moray but sadly it died as it stopped eating about 3 months after I got it. This is in no way unusual behaviour for morays in captivity, they get the urge to migrate but can't and instead they stop eating and die, from my research no-one knows why.
A Snowflake will catch and eat small fish and shrimps if it can but if it is kept well fed then it will not exert any real effort into catching them and if the fish/shrimp is quick enough it will get away. However, these fish need a good, varied and above all regular diet. If you go away on holiday and can't arrange for it to be fed then don't expect many inverts or small fish to be left in your tank when you get back!
Snowflakes require a minimum of 50 gallons to play in with a good amount of rock work to hide in. They are classed as semi-agressive and should be kept in reef conditions with caution. They are fairly easy to keep but can grow to around 18" and are very hard to handle so moving them from tank to tank when big is prety much impossible. Another important point to note is that they are very good escapologists and will get out of your tank if its is not sealed tight and if your pipework isn't grated/covered they will move down into your sump, etc.
Hope all this helps your decision.............my overall opinion of snowflakes: they are amazing creatures with bags of character but they are high maintenance fish.