when i first started my mantis tank i got crushed coral, will never get it again, i found out it would trap the poo and left overs of the mantis, when i went to go get the mantis, i had taken all of the crushed coral out, bought live sand(major rip off, should have gotten the dry kind) the sand looks so much nicer than the crushed coral, looks alot more natural, and if you found any thing to put in that tank im sure it would love the sand alot more.