I am having a new problem with bubble algae and was looking to get a few emerald crabs. From what I have found people say the ones with an hourglass on the underside are better but I have not been able to find a photo of what I need to look for. Does anybody have or can take a photo of what I should be looking for? Is there a tang or blenny that would be better suited for the problem? I have a 90g reef.

