Nonsense. They are very common. I used to get nibbled on by perch, sunnies while swimming all the time. Late summer the fish fry have cleaned out most of the insect larvae, and are starving, dumb, and still too small to be dangerous (the pinches can be startling, slightly painful, but no actual harm.)
Never known of a larger fish attack, personally. Maybe we only say an "attack" when people actually get hurt?
I remember perch nibbling at our legs as kids. I was quoting from an article about muskie (muskellunge), which are apex predators and can get to 30 kg / 70 pounds. I definitely don't want to be bitten - attacked would be a fair term, I think - by one of those.
We used to go fishing for those, too.
Yes, it was always the fantasy fish in my family: ever sought, never caught.
Which was just fine with me. I hated harming even sunnies.
Cichladae are *beautiful* to see swimming in the wild. Did you know that tracery of colour around the face but across the body lightens and darkens based on their mood?
C.
Amgine