Last year, my 3 1/2 foot long alligator gar died from overfeeding. I was so sad when he died. He's been with me for 2 1/2 years and I bought him when he was only 6 inches from a petshop in the Philippines called "Aqualand Alley". I miss the dude
I know he died of overfeeding because when we hoisted him out of his pond, his stomach was a little bloated. I also have this bad habit of overfeeding my animals (though I've gotten over it), my mom says its probably cuz when I was a baby we had this horrible caretaker ofr me who kept on forcing me to eat and hit me whenever I didn't (my parents didn't know about it and when they found out my dad almost wanted to hit the caretaker himself). I'm guessing it reflects on me though I've gotten over it now
One of the problems with overfeeding is it's easy to do. I eventually learned to do just a little and wait to see how long it takes for fish to eat everything. After awhile you figure out how much you can feed. I also do a disconnect on my canister filter while feeding so I can see all the left overs and turn it back on when the feeding is over. If you have bottom feeders, you can be sure that any left overs will be eaten.
The other thing about feeding fish is probably not to let family members feed them. They have a natural propensity to give too much food thinking it is good for the fishes.