Bacteriovorax stolpii is a species of bacterium in the family Bacteriovoracaceae. It is a predator that feeds on larger Gram-negative bacteria. These prey bacteria tend to live in enteric environments and have similar lipopolysaccharide structures. Bacteriovorax stolpii recognizes its prey by outer membrane protein receptors, which explains why Gram-positive bacteria that lack outer membranes do not serve as prey. They prey on bacteria by invading the interperiplasmic space where they feed, grow, and reproduce. Bacteriovorax stolpii used to be classified in the genus Bdellovibrio because of similar morphologies and lifestyle characteristics, however they were recognized as a new genus through phylogenetic analysis.