Out Of Tank Fish Breeders.

[ImmortalRav]

 
Has anyone ever tried these before? I'm currently running with two attached to my 20 gallon.

 

[the_lock_man]

And these are where you are putting the guppies that you have had problems breeding?

If so, it seems likely that the stress of being confined to such a small space is causing them to abort their fry.

 

[ImmortalRav]

No, no. The females are only placed inside, soon after they start to square out.

 

[the_lock_man]

This will still be stressing them. They don't know that you'll be letting them out after they've dropped their fry.
 
Try not using it for a while, and see if you have more success.