when I was in grade 3 or 4, I had a tiger oscar, without a lid, and I had another tank in front of that to keep the feeder fish in.. The oscar used to jump from his tank to the feeder tank, get his fill then jump back into his tank. Did this for months. Well one day he misjumped and landed in the litter box... I thought the cat had taken a huge dump and didn't notice the oscar missing in his tank, anyways a few hours later my mom noticed and confirmed that that "huge dump" was in fact my oscar

So I learned the importance of lids.