They just don't make tanks like that anymore.
How much did it cost?
Lets just say that its rarity commanded a premium price. I had a chance at one of these in the 8 gal. silver model from the same collector but I couldn't afford both. Probably last time I'll ever see a complete one of these for sale. I've seen a couple on ebay over the years but they didn't have the original glass which would be nearly impossible to find since they haven't made it for the last 50 or 60 years.