We dressed every night. I wore a dress, dh wore slacks and a golf shirt and boys the same. On Triton's boys all work slacks and shirts and ties. But we wanted to dress every night. I changed for the pirate party into warmer clothes for up on deck. If you do Triton's the night of the Pirate Party you might not want to dress for a pirate party, since it is the more formal restaurant. But on our night there (not the pirate night) there were a couple of men in shorts and t'shirts. I just felt they looked out of place, just my opinion. Most everyone dressed up for their Triton's night. Hope this helps!
But then again you will have been formal the night before, I forgot the party is in the same restaurant you dined in the first night. Hopefully someone who had that rotation can let you know what people did.