it doesnt bother the aro at all. its was just in front of the aro when the pic was snapped. the only fishes that charges at him are the parrots when they have eggs under the powerhead, and the aro wants the current.
Sorry to get u jumping! lolz I remember reading somewhere that some types of tiles releases chemical that is not suitable for fishes. Let me track back my re-search and post the infos.