I've read quite a few references to using lettuce as an alternative food source for some herbivorous inverts when tank-grown food sources run out. The sorts of things I've seen it recommended for are certain nudibranch and large snail species. Just wondering if anyone else here has tried it at some point, or has any reasons why it is ok or not ok to do? I've seen the lettuce thing recommended on Dr. Fosters & Smith, otherwise I would have dismissed it as bunk, since putting vegetables in a marine tanks seems odd to me. I use it as fw snail food and have done so for ages, but I'm just not sure how safe it is in marine systems, or if safety is dependant on water volume.