Though I'm jaded to my snake eating mice etc people really seem shocked and entertained by it but considering he gets 6 mice or 2 small rats a month over 14 years you do the math. Concerning fish back when I was a kid I thought of it as mixing up the diet of my cichlids and catfish; crayfish and minnows are free so hey bonus. My friends would help me out because they enjoyed watching it so all the better less work for me. My friends would pickup feeder fish sometimes and I thought the same thing mix up their diet their predators after all.
If I had them still the only reason I would hesitate is because of parasites like I said but even then I'd probably still put my living minnows and any crayfish I found in. It was just mixing up their diet to me; all my fish were healthy and long lived if I didn't have to give my big tanks up and move to an apartment who knows how much older my jack dempsey would of lived he made it to 11 I had to give him away at 10 sadly. I need to scan a pic of him he was a really big male with amazing colors.
Concerning anything parental for the most part I had a decent upbringing I was allowed a lot more freedom than kids in a city would have; taking a jab at my parents for letting me use feeder fish is a bit over the line. They liked my fish and animals also they encouraged most of what I did; where I live everyone hunts or fishes and we eat what we kill I was butchering deer when I was old enough to handle a knife; it's different from most people on here. I grew up hunting and fishing. I was also catching and keeping local species as pets. It was pretty much the norm. my grandfather had horses, cows, goats, hell he even had a pet fox.
Long time fish keeper most experience with CA/SA cichlids, natives like sunfish, and aggressive catfish.
Currently have a 29g planted with 14 candy cane tetras, 6 sterbai corys, 6 melini corys, a roided out tiger angelfish and 1 mustache wearing albino longfin pleco.
Oh and they all get along amazingly!!! went through 4 BN plecos and 2 angelfish until I got ones with the right temperament but it's the most mellow tank now.