The ruling about the mix of dead and alive fish at the time of fishing/the Grand Ayatollah Khamenei’s answer

The Grand Ayatollah Khamenei answered a question about mixing dead and alive fish at the time of fishing.

Question: At the time of fishing if it is noticed that some fish have been dead in water before fishing but are mixed with Halal and clean fish, and it is not possible to separate them due to large number of fish; what is the ruling in this situation? What is the ruling if the number is small?

The Grand Ayatollah Khamenei: Must avoid all those fish which are considered probable dead.