A guppy that is 3 1/2 weeks old can easily swim away from a HOB filter if they recognize the hazard that it poses.
I'd put her in a trap it looks like she Gonna drop fry very soon.
If you only have guppys or very small fish in your main tank then 3 and half week old fry should be fine
just put a few fry in to start with to see how they all get on together.
I would say leave her in the trap a bit longer. Mabye another day until she drops, I am surpried she hasn't to be honest.
Great photos fish48!
Congrats! I hope you get many more.
A guppy that is 3 1/2 weeks old can easily swim away from a HOB filter if they recognize the hazard that it poses.