The class

Class (biology)

In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...

 Flavobacteria is composed of a single order of environmental bacteria

Bacteria

Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

. Flavobacteria are a group of commensal bacteria and opportunistic pathogens. Flavobacterium psychrophilum causes the septicemic diseases rainbow trout fry syndrome and bacterial cold water disease

Bacterial cold water disease

Flavobacterium psychrophilum is a member of the Flavobacteriaceae family. It is a gram-negative rod-shaped bacterial pathogen that can cause bacterial cold water disease in salmonid fish. The disease typically occurs at temperatures below 13⁰C, and disease can be seen in any area with water...

. According to Bernardet et al., Flavobacteria are gram-negative aerobic rods, 2–5 um long, 0.3–0.5 um wide, with rounded or tapered ends that are motile by gliding, yellow (cream to orange) colonies on agar, decompose several polysaccharides but not cellulose, G+C contents of 32–37 %, and are widely distributed in soil and freshwater habitats. The type species is F. aquatile.