Why make life difficult for yourself? Most speakers would say 'a lot of'. We tend to use 'much' and 'many only in negative and interrogative sentences:
When you are eating it, 'fish' is generally uncountable. When you are catching it, it is generally countable.
There wasn't much fish in that fish soup.
I didn't catch many fish last night - two trout and a crayfish.
- For Teachers