White Mites On The Glass?

[dizzied]

Definitely neither of those, though I almost thought they were shrimplets at one point.

Fasted the tank, did a water change, temporarily added a betta. The population is down more than 50% now.

 

[Majjie]

They look like cyclops to me:

pic stolen from this web site http/bioweb.uwlax.edu/zoolab/index.htm

Obviously, only the females have the egg sacs - youngsters and males don't. I had them in a tank with neon tetras and honey gouramis once - they weren't quick enough to catch them but most fish will eat them. They might be a bit small to interest your betta!

 

[dizzied]

That might be it actually. I have seen something that resembles the egg sacs, though I assumed it was smaller pods attached to larger ones. The betta's been pecking away at some.