That's so cool, lol. I assumed (naughty!) that in nature, ponds would have natural aeration, eg wind/ rain, thus an artificial pond would also need the same. Expanding on that logic, I thought that if there is no oxygen, everything dies and gives off a really funky smell, as I've experienced with an old canister filter that I forgot to clean out lol. Interesting idea for a tank, much less "artificial" than the rest of us haha.