As far as I know, all shrimps will nibble on algae to some extent, but amanos do eat more algae than other shrimps. However, what shrimps are really good at is eating the extra debris in your tank - old leaves, leftover food, some bacterias that build up, etc. And by keeping those things cleaned up, they reduce the likelihood of algae.
In my experience, amanos are very greedy eaters. Sure, they do eat algae. But what they like best is to grab a piece of fish food, and sit in the corner of the tank, munching on the food they stole. So I was not as happy with them as part of my algae cleanup crew.
You will get varied advice on keeping fish with shrimp. Some people will say it is safe, some people will say it is not. What I have seen is that in a heavily and densely planted tank, you can try keeping shrimp with fish. It seems to be okay to have the shrimp and the fish in the tank together until the fish learn that the shrimp taste good. Then, no matter how many hiding places the shrimps have, the fish will hunt them out. You also increase your chances of this working by keeping very small fish. I have tetras in my tank, and they like to go after my cherry shrimp when the shrimp go swimming around the tank. Although the fish mouths are too small to fit a shrimp inside, the fish just pick at the shrimp and peck it to death. And a dead shrimp is a dead shrimp, whether it went into the fish's mouth in one piece or in many tiny pieces. So the advice "the fish is too small to fit the shrimp in its mouth" is not good.