Invertabrates keep dying!

[Toutouche]

I also agree with Mommy Often FW tanks have had Copper or some other contaminent added and it will stay in the silicone seams. A friend of mine had to buy himself a brand new tank when he switched from FW to SW, even though the old tank was perfectly good still.
By the way, NO, you shouldn't be freshwater dipping the inverts!! I was asking if you did and it could have also been why they died. It's called "Implosion". Basically, the inverts are used to a certain level of ( OHHH!!!! What's that word now??!!! The word that means a certain level of pressure/density caused by the water having salt in it) and freshwater is lots less of this dang word I can't think of right now!!! So basically they can have bubbles form. Kinda like getting the bends when you surface to quickly after diving deeper. Anyways, it's probably not that at all, although most inverts ARE sensitive to changes much more than fish are.

[MomRules]

Do you know where your tank came from? If so, ask if they ever medicated the fish in thattank. Snails really shouldn't starve to death in a week. Sounds very suspicious.