Yes, you shouldn't have a problem with a Snowflake Moray eel and a Tridacna. I have the same combination in my 125 gallon reef now with no problems of my eel trying to get a big meal. My eel has never tried to harrass my clam and if it did the clam would close up before it had a chance.
Snowflake eel make wonderful additions to a tank(even a reef) as they stay relatively small and have a good disposition. I would just keep an eye out for crabs and ornamental shrimp. I have had a Fire and Peppermint shrimp in my tank with my eel as well for over a year sharing its (small ecosystem) with my eel. _________ 125gal.w/Mag9.5 return(dual megaflow)>Mag7 pump Aqua Cev180skimmer.Wave2k Hamilton Reefstar(2)250watthqi(mh)pend.a Yellow, Naso Tang Red Lip Blenny Percula Clown Demoiselles Niger Trigger F. Wrasses Ceriantharia Orn.Shrimp and Stars Hermits Queen Conch asst. snails> Stars Zoos shrooms Montipora Brains Gorgonians Favia Turbinaria(large+small polyp) Acropora Xenia Tridacna (CroceaMaximaSquamosa) Leathers <35+75gal.reef tank as well> 
"IF THE PHONE DOESN'T RING...IT'S ME"  jb  | 
Clam and snowflake 
