I believe the expression is tighter than a Gnats ar$e, but my brother in law thinks it is Fishs ar$e. I have googled both and found both refered to - what do you think is the more popular.
wow, a quick search on google, and I have found: Ducks (most comon), fishs, and gnats.
Also: baboons, crabs, camels (in a snadstorm) parrot, bull, badger cat and dog's
Amazing
The basic association of the words 'tight' and 'ar$ed' dates back a hundred years. Strangely enough, the phrase originally referred to a woman who was not free-and-easy with her favours! Only later did it take on the meanings of unrelaxed' and 'mean with money'. Most of the later animal connections - duck, gnat, camel etc - were, typically, created in the USA.
The most popular is ducks, but i personally love 'tighter than a nuns crutch!'....talking about been tight did ya hear about the yorkshireman who got arrested for breaking into a tenner!.