One of the problems with hydroponics is high costs for fertilizer, while one of the problems with fish farming is the toxins that build up in a small body of water from byproducts of keeping fish in them. What happens with aquaponics, however, is that the fish byproducts are funneled to the plants as fertilizer, while running the water through the plants cleans the water and keeps the fish healthy. Neat, eh?
Here is a video explaining the process:
Here's another garden set-up - looks like it could, ahem, fit into a garage quite nicely!
Here's a guy doing it in a small greenhouse:
I think it's a pretty neat concept, especially if some of the claims of plant growth are true, plus having the ability to grow several crops a year, it could be well worth the money to have a little food-production corner like this, saving you on ever-rising grocery bills.