I've had a few emerald crabs, and I've had good experiences with them cleaning out the bubble algae. My current crab cleaned out the algae when it was in my 13 gallon nano. I upgraded tanks, but now the stupid crab hangs out near the same rock all the time and bubble algae is getting out of control in other parts of the tank.
I'm definitely going to get a couple more crabs as soon as possible.
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