It's cool, but not really the proper environment for a fish. Would make an excellent Endlers tank, or Galaxy Rasboras. Looks impossible to clean though.
Especially for a family of 6 lol. It is not a dining table. It is a desk. The top comes off. You could fit your arm down there no problem. It would definitely work for guppies, a few tetra, danios, and all of the other fish that FAIL...lol I saw one on Ebay that was 90 gallons and had pretty good dimensions. It was 20"wide and like 3' long. Imagine having a lungfish or something in your desk like that. People would be impressed.