The bug things on your glass are limpets they’re harmless
The bug things definitely have legs - I can see them when they are crawling across the leaves, swimming, or walking over and into the gravel. That would eliminate limpets as a suspect, no?
I tried getting a clear close-up of one today; they are smaller than baby shrimps, and most have a striped or marbled pattern like in the pic. They mostly congregate in the gravel although I see them all over my tank nowadays. What does anyone else think?













