I have 2 of them...they're each about 2.5" long right now, I think they'll cap around 3", so fairly large as freshwater shrimp go, and totally fish and plant friendly (they climb my big java fern occasionally to get closer to the filter output) as long as the fish aren't big enough to eat them. They're big enough my Aussie rainbows and betta ignore them. You can see they have fans instead of claws, they filter microbes and small organic matter out of the water and then stick the fans in their mouth to eat it all up. They usually stick to the high-flow (filter inputs/outputs) areas of my tank to get the best filtration...it's important to have a mature tank for them or there won't be enough food in the water and they'll take to sifting the substrate with their fans to pick up mulm, which eventually wears down the fans and then they'd really starve to death. They're awesome to watch, they'll filter for hours in one spot then suddenly zoom somewhere else. They were light brown when I bought them, but I read the happier/more well fed they are, the darker/redder they get...so mine seem to like their new home