Good point. Didn't Reagan's Navy destroy the entire Iranian Fleet in the 80s?
https://en.wikipedia.org/wiki/Operation_Praying_Mantis
Not exactly. Iran had a small navy and losing a frigate and some patrol craft was significant. It disrupted Iran's ability to interfere with commerce in the Persian Gulf and sent the message Iran would face direct consequences for attacking anyone.
(Does that sound remarkably familiar to current events?).
For battle where a entire navy really was wrecked, there is the Battle of Bubiyan during the first Gulf War. Royal Navy Sea Lynxes firing Sea Skua missiles took out most of the Iraqi navy. In total 21 of 22 Iraqi warships present were destroyed.
https://en.wikipedia.org/wiki/Battle_of_Bubiyan