Vampire Shrimp vs Bamboo Shrimp

[jaydivingboard]

I've read they get huge in terms of shrimp (up to 6 inches) but I want 2 of one or the other for my 40 gallon breeder but don't want it to be way too big for my tank, what is the biggest one you all have raised?
Also I only want 2 because I wouldn't feel right having a loner shrimp because they seem to be extremely social

 

[Feohw]

Bamboo shrimp stay smaller, so stick with them if you're worried about size. In aquariums vampires don't tend to get to 6 inches all the time. It seems as though 3-4.5 is more common. Bamboos should get around 3 inches. Up to 4 inches even.

My vampire is 5-6 inches.

Definitely get more than 1 if you can. And remember that they are filter feeders, they eat micro-particles rather than whole foods.