Justify this snail death

[Delphinus]

I've moved my abalone between tanks a few times. I take a piece of plastic (I think it's for lighting, not sure what it is - think "really thin acrylic"), put it on the glass next to the guy, and then poke the foot of the abalone until he's annoyed enough to move. Then I keep slipping the plastic in front of him until he walks onto it. Sometimes it takes a few tries and a few minutes, but, perseverence will win over eventually.

I drip acclimate them though between tanks as I've noticed that even with similar water conditions the change in water chemistry knocks the wind out of them. They'll not move a whole heck of a lot for about a week after a tank swap so I figure the longer the acclimation, probably the better.

Amazing herbivores. Almost as good as a seahare, but seem to be less prone to starving themselves out. Nevertheless I have lost a couple, shortly after purchase, that I suspect may be due to starvation. Ie., bought them, then they never really did much, never ate anything, and eventually perish. I think I've purchased .. um .. 3 or 4 of these guys over the years and it's only the one that I've had for 3 or 4 years now that's still with me. So the success rate doesn't seem to be 100% with them.