Do they cause any problems when they all die off at once in the fall?
Last year was my first year with tilapia, so I am no expert.
I never noticed a mass winter die-off.
Maybe it's different in Texas where it stays warmer longer,
but eventually when it got cold I assume they all croaked.
There was no mass die-off with bodies laying everywhere,
in fact I only saw two dead tilapia after it started
getting cold and I had stocked over a 100 lbs of tilapia
which I observed were very active throughout the summer
and fall in my 4 acre pond.
Not sure if the the bass/hybrid striped bass/hybrid crappie
gorged on the tilapia as the tilapia metabolism slowed down, or
the tilapia just dropped to the floor of the pond to rot
and get eaten by catfish.
Whatever happened I can tell you it was not an issue for me.