[3] When grown on Cytophaga Agar, F. psychrophilum produces bright yellow colonies with thin spreading margins not greater than 3mm in diameter.

[3] On its fish host, the pathogen can be found on external and internal sites such as skin/mucus, gills, brain, ascites, lesions, mucus, kidney, spleen, and reproductive excretions of spawning adults.

Secreted proteases result in a mixture of amino acids and oligopeptides that comprise the main source of carbon, nitrogen, and energy.

[3] However, its inability to produce fruiting bodies or degrade complex polysaccharides considered this classification inappropriate and was then suggested to belong within the genus Flexibacter.

Genome analysis revealed that sugar kinase and phosphotransferase systems used by bacteria for specific carbohydrate uptake are absent.

Gene FP1110 and FP1111 encode for cyanophycinase and cyanophycin synthetase may serve as a storage compound for carbon, nitrogen, and energy and allowing the organism to survive in low-nutrient conditions.

Affected fish first display a whitish discoloration along the exterior side of the adipose fin then eventually progresses to invest the entire caudal peduncle.