The Fish Tank is a very traditional place run by Thai Chinese. It is a form of prostitution that is deeply rooted in Thai society and there are hundreds of similar places throughout the city. Since prostitution is prohibited and the King says it doesn't even exist, these places started out as actual massage parlors with the color of the girls' numbers referring to the kind of massage they give. The establishment shown in WHORES' GLORY is fairly upper middle class and it is in a district with many similar places. It's the type of place where local businessmen also go to have a drink or eat something. Massage parlor culture has nothing to do with the so-called sex tourism that Thailand is infamous for.