Very nice! This does happen a lot. 2 fish in quarantine start laying eggs. Get to wigglers than eat them. I’ve got a pair I bought in June been doing this regular. Just once did they make it to swimmers. Of that hatch 14 lived. They stayed with the parents for about 6-8 weeks then I had to remove them. Since they’ve eaten the eggs every time.
The standard cage wire used to cover the cone can be used to block them from getting to the eggs on glass. Cage wire can be bought at Home Depot.