They are 100% peaceful IME. Far too tiny and fragile to cause any harm to anything. Mine live with least rasboras, cherry shrimp, a couple other species of small rainbows and snails. I've only ever seen them snap at a stray new born shrimp as it was swimming though the open water, otherwise they are perfectly harmless!
I have about 20 in with least rasboras harlequin and CPD's and they are the least quarrelsome in the tank