In my experience with ADFs, you might want to watch for their personalities before putting any dwarf shrimp in the tank, especially red ones
like you mentioned, they are pretty poor hunters but at the same time, some of them can grow up to be quite skilled hunters as they reach maturity. I had a male and female ADF pair and the male was dorky and sweet and pretty much blind but the female was definitely not blind at all, in fact I would say she had excellent eyesight and scarily accurate lunge/aim and very aggressive towards anything she could fit in her mouth, including all my dwarf shrimp (the red ones went fast) and my chili rasbora. She decided to treat herself to many expensive meals until I gave up buying any more small fish/shrimp because she would just eat them all. The tank is now her kingdom.
Fortunately though, I have 6 amano shrimps that are smart, speedy and too big for her to catch. They've been there since the beginning and have survived it all lol! They aren't even scared of her and even bounce on her head once in a while which I find hilarious. I tweezer feed my ADF so there usually isnt much waste but the amanos always come to the tweezers for a juicy bloodworm and I give them each one as a treat. They love it, but since they are always grazing its only a small portion of their diet.
I also have an oto but it doesnt eat leftovers or waste. Just grazes on algae and I give it algae wafers, which the amano's also love and help clean up since the oto usually can't finish it all.
I would also like to add that with that many ADFs, you'll probably have a breeding pair. They will most likely breed, multitude of times with hundreds of eggs so if you are inclined to do something about that then maybe do some research beforehand so it doesnt catch you by surprise when it happens and you can prepare for it.
Thank you so much for your response!
Long story short, I was "babysitting" ADFs from my school and they had tadpoles, which I helped raise before returning them and their children to a very excited owner lol.
But anyways I am lame so the whole eating eggs and tadpoles dying, not to mention the fact that my female seemed distressed, really got to me. I'm trying to avoid it, and my LFS says they will adopt and switch out frogs with me. I have four, and I think at least 3 are male, we'll see though. Gotta wait for them to develop.
Anyways, I'm definitely leaning towards shrimp, but maybe amanos is a better idea, size-wise (unless there are some other big guys ?).
I've heard you need 6, and my tank is only 15g, 4 frogs as I've said. Is there enough space? I don't want to overcrowd obviously.
Also I love that you call it her kingdom omg.
I'd love to get into shrimp eventually but for now, I might have to wait. For the amanos, I know their eggs can't hatch in our water, but do they lay them anyways?