If I remember correctly (and just for reference, that's a standard 20 gal next to it), the dimensions are: 12"deep, 16"tall, and either 30" or 36" wide. I put in the one baffold, so you can scrape that out and put it in wherever you need it, or make a new one. It does have hole drilled for an external pump, but I never used it, so I pluged it. There is a bulkhead already installed.