Aquaria
My other interest is naturalistic planted aquaria (also known as Nature Aquaria). I don't own a tank at the moment but this is a temporary hiatus. As a hobby for naturalist technophiles like me I can recommend it. My most recent aquarium (below) featured a custom built CO2 injection system, metal halide lights, dawn-to dusk (and even moonlight) lighting, undergravel heating, surface skimming, automatic waterchange, automatic feeding, UV water sterilization, etc. The plants literally "fizz" oxygen bubbles into the water when the main lights are on—very beautiful but it means a lot of gardening work as plants grow quickly! Half the fun is collecting and trading rare plants. One thing you learn however, is that any plant or fish looks great when healthy and happy. One day I might create a nature aquaria website.
My most recent aquarium; L1200, H 750, D 600 (mm)