There exist humans who can crawl into the memories of others and manipulate them to their advantage. “The company”, a system that succeeds in merge and acquisition deals, owes its rapid growth to the misuse of said abilities, but an attack by rebels of the same kind makes the plot thicken.

“Even if I’ve lost my memories, can I still be myself?” A psychological suspense drenched in blood and tears.

Fish is the sequel to Pet, a manga by the same author, and its translation isn't complete yet but there's an anime that covers Pet fully.

I strongly recommend knowing Pet's story before reaching Fish's 3rd volume!