Yea it is in a older tank which went down in livestock from 20 to only 5.
Saw them worms already before in tanks that I no longer used and was to busy to empty them out at that moment.
So I guess this is kinda the same, they looking for food but only thing in the tank are 5 guppies and snails.
Don't even see them beside when I was cleaning the window so probably one woulda been on the cleaner. (the video)
All you need are guppies, and snails...