Hi. I have had those in an aquarium back in the days. The days when it was possible to spend half of my holidays knee-deep in ponds, lakes and rivers.
They are quite abundant where I come from. Small individuals can be found under rocks and logs in shallow water.
They usually did start feeding during the day when offered pieces of fish or such. Other than that absolutely no activity during daylight.
Coldwater tank, of course. Lots of oxygen.
They did allright in an aquarium, at least when quite small. Mine were about 2-3 inches when caught and less than 10 inches when I got rid of them.
Smaller fish disappeared one by one.
The largest I've caught (fishing with a net) have been almost 3 feet long.