To the best of my knowledge, lime isn't necessarily bad for the fish but it will raise your pH quite a bit. I could definitely be wrong but i doubt the lime in the water killed your gold fish. What size tank are your fish in and what are your readings for ammonia, nitrite, nitrate and pH?
/www.fishforums.net/index.php?showtopic=196807&hl=
/en.wikipedia.org/wiki/Limestone