tiger tail cukes (Holothuria spp): toxicity and sand grain size?


10 & Over Club
Thinking of adding a tiger tail cuke (Holothuria spp) or two to assist in cleaning/upkeep the sand bed.

I have read they are not toxic should they perish (like most other cucumbers)...anyone know 100% whether this is true?

Second question, will they be able to 'eat' the sand if the sand is the 'Special Reef Grade' sized grain for 'plenums'... 1mm to 1.7mm grain size. Not fine oolite sand.
Tiger tails dont' seem to be that toxic, i had 2 of them die in my tank due some power issue and the rest of the tank was not affected, they typically like sand no bigger than 2 millimeters.
I had one die in my old 75 with no noticable effect on the tank. It was a dsb system with mostly softies though, so not the most delicate inhabs.