Book about Mutated Fish? main character was a male who ended up searching mutations in toxic river water. At first they didn't know what was the cause because fish had started to grow bigger. The river was located somewhere in Russia.

[Merli]

Hello, i read something a while back and this is all i remember of it:

I might have forgotten some important details but any idea is welcomed!


- main character was a male who ended up searching mutations in toxic river water. At first they didn't know what was the cause because fish had started to grow bigger. The river was located somewhere in Russia.
-It was probably a russian author, but i can be wrong.
- i am not sure if he was invited to a crew or maybe he was the leader of a crew. But i remember a young girl joined them and he ended up liking her. The year gap was quite big but they both started to love eachother at some point.
-i think the fish (plural) at some point tried to kill him and his crew. There was some kind of action going on but i don't remember..!
- The main character was good at karate. (for some reason i remember that)
- I remember main character looking back to his years.
- Not sure how much it helps but i remember the book cover had a fish on it.. with a big eye.. but that's very vividly in my head.

So, does anyone know what book it may be? It was just a random book i found at my old house, i had nothing better to do so i ended up reading it. So the book can be quite old.

Thanks in advance! Any suggestion is welcomed!

[Lobstergirl, au gratin]

Merli, was this fiction then? What year did you read it? Was the mutated fish the main plot, or a side plot? What genre is the book?

[Lobstergirl, au gratin]

Merli, are you still looking for this or did you find it?

[Lobstergirl, au gratin]

No response. Moving to Abandoned.