65g reef

[Melina]

I believe I just identified them.. they're tiger tail sea cucumbers...
Will they be OK without a substrate for a few days? There was a bit of die-off on my rocks and I wanted to syphon it out and let the rock cure completely before adding sand so I could syphon out any stuff that falls off the rock. I wasn't planning to put my sand bed in right away. Also I was not planning to make a deep sand bed, just 1-2 inches... will this be OK for the cucumbers, and will they survive the curing/cycling process? The rock was cured, but there was some die-off during shipping. Not much though.

Are these guys really toxic if they're stressed/dying, or are they safe to keep in a mixed reef? Do I have to worry about them poisoning my tank? I don't plan to have many fish, just a couple clowns at the most, if any. Will they kill my corals, if they die and release their toxins?