Agua Mala

Peculiar description of the fish on pages 34-37 but I'm using quotes from page 36.
"They were immune to it's poison"
then later on on the page
"But these poisonings from the agua mala came quickly and struck like whiplash."
My idea is that the fish Hemingway is talking about could be life during his depression and his Mood swings. Hemingway says other fish are immune to it's poison and I think that means that other people aren't as sensitive to problems you face in life. (Depression can cause a lot of mood swings)

"They were immune to it's poison. But men were not..."

They = Great writers (other than Hemingway) or "normal" people
it's = critics/general public
poison = criticism (a unique word word choice on Hemingway's part b/c the first thought the reader thinks of when reading the word "poison" is death)
men= Hemingway struggling with his writing career

Hemingway may have envied others that were not affect by critics. This statement displays Hemingway's vulnerability towards those who constantly try to "poison" him.

"But these poisonings from the aqua mala came quickly and struck like whiplash"

The word "whiplash" made me think of Hemingway feeling tortured (mentally anyway). Initially, the impact from poison hurts, but there is an after effect that is similar to whiplash. The pain that a whiplash causes does not last for a short period of time. The pain will continue well after the impact and sometimes it could also result in a scar that could never be healed.

Could these poisonings and/or whiplashes have scarred Hemingway to the point where it will never heal?