some snakenecks only come out of the water when no-one is around watching
i dealt with 2 snakenecks that had been kept in only water for 6 years
no basking area, 2 normal flourescents and fed only oxheart as that is how they were told to keep them on purchase
they were like picking up 2 sponges
sadly the tank cracked a few months later, all the water leaked out and the 2 turtles died
as their shells weren't strong enough and collapsed onto their lungs
turtles shells are effectively their rib cage
give them the option of basking, correct lighting and diet