I went to the Coral Room last summer with a buddy of mine. First advice would be to get there early because the line can get long especially on weekends. Once inside, you are automatically struck by the decor. There is a large fish tank behind an elegant bar and the great thing is, there aren't only fish in the tank. There are "mermaids" who swim in and out of the see-through tank all night. It's quite a spectacle.
As are most clubs in NYC, the drinks are fairly expensive. The atmosphere is nice and luxurious. There is a dance floor in the back and the music wasn't too bad.
The night we went, some high school senior class decided to have an informal party there and wwe were stuck with a bunch of young kids. It felt weird because everyone else seemed to know each other and my friend and I were left wondering what was going on until we asked one of the girls.
Overall, it was a nice experience. Not the best club I've been to in the city, but far from the worst. It is defnitely worth checking out once