Yes, they are supposedly a species of Machrobrachium, and they are also supposedly predatory. I have heard from people who have lost small, slower fish to them, i.e. neons and cardinals. They look a lot like a ghost shrimp, but they get quite a bit larger.
They will attack and kill (eat) other shrimp species and basically anything else they can get their claws on. Cute when they are very small, probably not so cute once they start growing up.
My LFS sells is run by some really knowledgeable people (a husband/wife duo who were actually the founders of one of our local aquarium clubs), they sell whisker shrimp but mark the tanks with big warnings about them, telling people outright that as these shrimp grow up they will wipe out peaceful dwarf shrimp species (things like RCS, Tigers, Bee, Amanos, even ghost shrimp) as well as anything else in the tank slow enough for them to get their claws on.
I have a macrobrachium and will confirm this. Macrobrachim, not sure if all, but a number of species will prey upon other fish species in teh tank. Not necessarily slow fish either. my zebra danios had some encounters with claude until I moved her to a 5.5 gallon tank all on her own. I feed her house flies.
she has nipped me with her claws AND DREW BLOOD.
They are also opportunistic predator.
Whisker shrimp may not be as dangerous as a macrobrachium pilimanus, but be careful.
My LFS carries these too and they look to be Macrobrachium sp. 'Red Claw'. They get about 3" long and breed readily in the aquarium. They're quite fun to keep, though they will fin nip fish. They eat snails too. You can keep top dwelling fish like rainbowfish without any issues as these "Whisker Shrimp" will stay on the bottom of the tank.
the claws do seem too small to do any damage... but watch if they get larger. sort of reminds me of a ghost shrimp, but I know it isn't. Just watchit. if fish go missing, it's possible your shrimp is having a snack
Can't find much on Macrobrachium lanchesteri but from the pics I find, it does resemble the one I have. And so far so good as far as being peaceful. I have about 15 cories and I watch him climb over them with no interest. I'll keep an eye on him though. I really like him because he is so active all over the tank
I still haven't had any issues with this guy. But he is a wild son of a gun.
Everytime I put my hands in the tank...THERE HE IS. Looking at me. I could be on the left of the tank and he is right there so I go to the right and holy hell, he's over there looking at me.
Once I just wanted to see what he would do...well he climbed my finger and up my arm to where i have some hair and it looked like he was just playing in it...but then I felt it. He was either pinching, pulling or biting. Didn't hurt as much as startle me. But he is determined to be wherever my hand is everytime I put it in the tank. He'll even sneak around the back of plants to where I don't see him until he is right on me.