I would imagine that diving in an aquarium is one of those things that frequently comes with buyers remorse unless the people doing have very limited experience fish watching in the wild leading up to it.
In January I drove out to TODI near Antwerp Belgium (
https://www.todi.be) which is big round tank/pool that slopes towards the center where it is 10 meters deep (average depth is about 6 meters if I recall). It is filled with lots of different freshwater fish and various structures to provide habitat and to make the diving more interesting.
It was a neat experience for the first 15 minutes...but by 45 minutes it was really kind of boring, and there is plenty of room to swim around as the diameter of the tank is 36 meters across. There is no monitor to shake an angry finger at you unless you do something severely out of line such as chase after the fish or purposely cause damage to the structures in the tank.
You get 2 hours for 30 to 37 Euros (depending on the time you go) and can pay for more time if you would like (the 2 hours includes the time to get dressed out for the dive and the time it takes to change back into street clothes).
It is one of things you do to say you have done it but is just kind of a meh experience that you would not rush back to do any time soon.
I can only imagine being confined in a smaller tank at an aquarium under the watchful eye and rules of the staff....after the fish swim by you 2 or 3 times you will be ready to get out and have a beer.
I really can't fathom being in that situation for more than 30 minutes...nor can I understand why anyone would pay the fees the aquariums are asking or putting up with the long waiting lists.
-Z