are there any fish that certain cultures worship?

Go ask a Bangladeshi.

I can think of some Ancient Europeans ones who did.

Unless you want to count the Leviathan, but it's not something you worship.

Yes, totally there are.  Let me tell you the.... hold it, did you say as an official religion?  Then that's a no.  No major religions that I know of worship fish, or even regard them as sacred animals.  Not officially.

But as a practising Pastafarian (Church of the Flying Spaghetti Monster), some of us do have a fish species that is considered pure and worthy of our undivided attention.  It's that fish that lives in women's underwear that nobody can ever find.