mistahoo - Those shrimp doesn't quite look like amano shrimps. Amanos have a distinct pattern dots and blotches. If they breed in your tank they are probably malawa shrimp. They could also be a different type of "algae eating shrimp". There have been a lot of mysterious "algae eating shrimp" being mixed in with amano shrimp shipments a lot this year. I've seen these shrimps a long with amano shrimp at lfs around here and they do look a lot alike. But if you look closer you can tell the difference.