I find it easy, every day it is a new hog, same girls just always different. The key is having them jump for food or distracting the other girls. It seems challenging at first but soon you will get the hang if it. Maybe it helps that I have floating plants that break up the surface? I don't know, but two of my girls are slower eaters. I make sure they all get at least two pellets
I added one girl that has a gill flap that is missing, her mouth is also small but the flap may gift her a tiny bit so she doesn't open her mouth all the way. So I have her get a pellet then she usually swims off with it if she can't swallow it. She will come back after she swallowed it.
Once you get your girls settled you should familiarize them with your hand and such. My avatar was taken like 5 minutes after I got the first girl to go on my hand. They are fun to have though. Two of mine sometimes jump fully out of the water and across the top like 4 inches. And now I am rambling completely off topic lol.