I'm assuming these are flatworms, but I can't find anything that's both white and the same shape. So far, I've only ever seen them on the glass, never on any of the corals (invert only tank), but if they are on the corals, it's possible I'm not seeing them (though I have been watching). I've been seeing them for probably 6-12 months and their population may fluctuate but it doesn't appear to be getting out of control.
These are range from about 1 to 3 millimeters long.
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These are range from about 1 to 3 millimeters long.
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