Hmm, I'n not sure what they are, but they do look like the "fish lice" isopods. They don't bother any of the fish though (and I've had the same rocks with some of the fish for over a year).
They do go nuts if I do a night feeding or if I stick my hand in. The largest one I've seen thus far is only about 5mm long.
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32"x32"x20" Cube-ish tank
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