In this very relaxing video, a man tends with infinite care to the precise ecology of his unfertilized nanotank: a tiny yet thriving 5-gallon world of flora and fauna. The best moment comes when he drops a slice of boiled cucumber in. A redditor explains the significance:
The only caveat is that this person has not used fertilizers or CO2, which most people who care for planted tanks do. He's a achieved a really beautiful tank even without those components. It does help that this is a really small tank, though. However, smaller tanks are a lot more fragile and prone to failure because of their size. Even minute changes will in nitrate/nitrite levels can be devestating. The cool thing about naturally planted tanks is that they eventually form a self sufficient ecosystem that can balance itself very well.