I bought a 300 litre aquarium about 6 weeks ago for the living room. Added soil, plants and water. Have spent the last 6 weeks watching plants grow, and snails that smuggled in on plants, multiply. I over fertilised it and left the light on accidentally for a couple of days whilst I was away and experienced an algae bloom, which was interesting. Added some cardinal tetras and amano shrimp yesterday and have spent a lot of time just watching them potter around. Has been a nice change from looking at a screen.