As A Matter of Fact
First, let me say I don't dislike fish, but fish dislikes me. It's hell when you love the taste of something and then pay the price for it. Doesn't matter if fish are fresh water, under bice, deep sea, the ocean, or for that matter Mrs. Paul's Fish Sticks (and they aren't real fish), I have severe allergies. Enough of my personal problems.
Are there plenty of fish in the sea? A euphemism meaning there is one more man or one more woman out there to be found to have that all important lifetime commitment with. That need to fill the gap in one's life.
Honestly, there are more fish than there are humans on the planet. And they multiply faster than does the human race. But they are a distant second to ants which numbers in the billions, hence that other phrase, "ants in your pants".
Overall, the planet can contain over a trillion varied species.
But I digress. As long as the girl doesn't kiss like, or look like a fish, I wouldn't mind getting to know her.