What in the world is this?

[noirsphynx]

Nope not even the slightest tinge of yellow, he's a mottled stone grey color.

Thanks everyone for their help, it's appreciated

Also, this morning during my morning tank check I found 4 teeny tiny snails, too small to probably even take a pic of. I took them out just to be safe so now I need to try and find out what they are. Annnnnnnnd my nassarius snails keep laying eggs all over the glass, lol. Salty tanks are definitely NOT boring =)

Originally Posted by justinl

oh okay, no doubt, that's a filter feeding sea cucumber. They're basically like any other cucumber except for the fact that they filter feed. Because of that, they don't really care where they sit, sand rock or glass.

Many cukes are toxic so be wary. There is a yellow variant of what you have, same size, that is toxic and may or may not harm a 24g if it dies; they tend to find pumps or just die because they're unhappy. However, i do not know about yours. is it even tinged yellow?