Its all your opinion on what cruelty is. I often feed my fish when I have guests over, it gets them moving about and allows all of them to be seen. Being a fisherman, I thought nothing of dropping a worm in the tank but I made my guest cry at my cruelty. Even still, I somehow see it as somewhat cruel to watch a worm get ripped apart by my smaller fish. I still see it as a natural prey item and fact of life, even if I am the one controlling it. I keep fish because I love fish and their natural behavior. I try to make my tanks as natural as possible even if they are still in a "small glass box." A predator hunting their prey is part of their natural behavior and I enjoy occassional live feeders. But I enjoy watching my predator hunt, not the sick demise of the prey. While it is one and the same, there is a thin line difference. I know, contradiction.
On the topic of mice as feeders. Feeder fish and the like are in their element, the water. Feeder mice however, a struggling to get away AND get out. Its like a person having a fear of drowning while knowing the shark is after you too. It does seem a little extra cruel.
While it might not be a staple or a healthy "treat", mammals do fall in the water and fish are opportunistic. An occassional mouse is not a terrible item to feed to a fish. When my snakes refused their thawed meals, I would sometimes offer it to my large catfish. While I know it wasnt the healthiest thing, the large meaty meal did create a large growth spurt that did not happen with a healthy pellet staple. the difference between normal feedings and only eating a mouse was a growth difference of over a 1/4". That pattern was repeated any time a mouse was eaten. On the other hand, what wasnt digested(fur, bones etc) was incredibly messy and terribly rough on filtration. From a dietary standpoint, a rare offering of such a meal can be good for growth. Like how a Big mac is great for growing out your thighs
Waay more PC then me
