Softshells can get BIG. I've heard you can eat them like you do snappers, although I haven't tried it personally.
Not suggesting that you eat your pet.
I had never seen a big one till last year. They are very reclusive and so even as a kid that spent a lot of time outdoors had only seen a few, most under 6" long. They were highly prized possessions if there were any turtle races coming up as they were FAST.
Last year grandson said he saw a huge turtle in the main pond that had feet like fins. I figured he just saw a snapping turtle but what he described was different. A week or two later I spotted it crossing from the sediment pond to the main pond. Did not get to look long because as soon as it saw me it was gone into the water in a flash.
Biggest soft shell I ever saw for sure. Front to back of shell I'm guessing at 14". Big as most of the snapping turtles we see.
They are neat looking turtles. I think it must have moved on. Maybe a female laying eggs nearby or something. Never saw it again.
And sprkplug, I'll take the chicken and eggs any day of the week. Never ate turtle, though my older brother has several times and says they are good. He eats all kinds of weird stuff though so I don't put much faith in what he says is good.