I recently inherited 2 fish tanks. The first one which I have up and running with 2 young fancy guppies GloFish 1.5 Gallon Aquarium Kit at PETCO and the only thing I added was an air stone and some plastic plants. The second tank is what I believe to be a 2 gallon Hagen that came with an Elite Mini A-130 Amazon.com: Hagen Elite Underwater Mini Filter, UL Listed: Pet Supplies filter system. The Hagen has a nice crack on the back pane, which has been repaired and lasted 48 hours without leaking. I was thinking of setting up the Hagen and cycling it and possibly adding guppies as my 20g is getting loaded. Then I may retire the 1.5g or possibly sell it. Thoughts?