Andy Sager
Aquarium Advice Addict
Boy, this is a tricky one
I used to feed enough shrimp at each feeding that there was some left over in the tank overnight. HOWEVER, I judged it so that there was no more swimming brine when the next feeding time was. So, for example, if there was still swimming brine at lunch time feeding, the lunch feeding was delayed that day. Same with dinner. The thing I watched out for was the dead shrimp polluting the tank and fungusing over so I routinely siphoned the bottom of the tanks a couple of hours after the morning feeding. Usually, every other day but it was always situational. (It's an eyeball thing, not a measurable thing, for me. 
) When the fry are small, you want to make sure they have enough to eat to get them to grow so the 3 minute rule is not really a good measure at this point. It really comes down to more of a: Hatch out a measured amount of BS eggs. If they eat it all, add some more eggs for the next same time feeding. If they can't finish the shrimp, cut back on the amount of eggs you are hatching until you find the happy medium. (Hence the reason for records )Lastly, losing some fry is normal. I believe the percentage for large brood wild animals and fish is that 10% of the young grow to become breeding adults. Predators, genetics and the siblings themselves all play a part in the surviving 10%. Obviously, in a tank, the amount of fry that would normally be eaten by predators is diminished but that still leaves the other 2 parts at least that you have no control over at a young age. My magic number was 100 & 150. If young breeders yielded 100 salable fry, I was happy. If my older breeders yielded 150 salable fry, I was happy. Anything more than those numbers and I was really happy. Too many more than those numbers and I would start to panic looking for more pools to grow them out in.
Just remember, use each spawn as a learning tool so you get to the point where nothing surprises you.
