Generally Keep fish AWAY from turtles.
Turtles will eat most things they can catch, as in the wild fish are a staple part of their diet.
You can get a few exceptions.
Ive kept convict hybrids that have lived with turtles, and there is even a pakistani loach whos
keeping my turtle tank clean. BUT my turtles are pretty laid back, no biting behaviour, confident
and always wanting attention. If your turtles are the sort that want to be left alone and can be bitey.
keep fish away.
For the mississipii maps, im sure you know their eventual size.
And the fact they are much more aquatic compared to species such as the
yellow bellied slider, so require more swimming room.
Pm me if you're after more information.
But honestly ethically, Fish + Turtles = Turtle Food.