I had the same thing happen to me only with nightcrawlers. I used to feed my fish nightcrawlers alot. Then I stopped for a good two months, when it was time to clean my FX6 I had about 3 large nightcrawlers on one of the media trays and about 10 or 15 baby nightcrawlers!!! They were alive it was the craziest thing ever and I have never seen my fish let one go into the filter.... weird.
Sent from my SAMSUNG-SM-G870A using MonsterAquariaNetwork App