I don't know whether this is feasible at the temperature gradients created by data centers, but it's not prohibited by physics. If there are chemical species in the water that are stable at 24 C and not 19 C, the fish can harvest these for chemical energy after they have traveled the ten meters.
This is probably more relevant at temperature gradients greater than 5C, but it's thermodynamically possible.
This is probably more relevant at temperature gradients greater than 5C, but it's thermodynamically possible.