I don’t have a positive ID on these things but they seem to be native darkling beetles (Tenebrionidae) that hitchhiked on some grapevines I added to my tank.
At five millimeters long, they’re a little bigger than my mites but the populations don’t seem to be conflicting (not that I see much of either anyway). I only know I have beetles because they keep showing up in my saltwater pool.
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