Pseudomonas aeruginosa is fairly easy to differentiate on blood agar. Colonial morphology, odor, and fluorescent pigment are important characteristics to observe. Peudomonas aeruginosa colonies are irregular, spreading, translucent colonies usually showing a bluish-green ("gun metal") pigmentation that often diffuses into the media. Pigmentation production is best at room temperature after 48 hours. These colonies also have a very distinctive aroma and are beta-hemolytic.

Colonies of Pasteurella multocida are white and very mucoid. They tend to grow into a confluent mass of white slime.

Aeromonas hydrophila form large colonies that are very beta-hemolytic.

Colonies of Moraxella bovis are white and smaller than those of Aeromonas. They are beta-hemolytic, as shown in this slide.