There are 5 fish and 2 of them druned how many fish are there now?

There are still five fish since fish can't drown.

If you are trying to correct the sentence, your answer is:
There are 5 fish and 2 of them drowned. How many fish are there now?

But if you are not trying to correct the sentence, 
Then probably there will still be 5 fishes as fishes can't drown

Hope this helps :)