Morphology changes of Flavobacterium columnare starved cells during revival in different nutrient media. Panels A and B, cells cultured in Modified Sheih (MS) medium at 4 h post-inoculation (arrows point to small membrane vesicles). Panel C, a cell cultured in diluted MS (MS-10) at 4 h post-inoculation (arrow indicates fimbriae). Panel D, active cells division observed in MS-10 cultures at 12 h post-inoculation. Panel E, cells actively growing in MS at 36 h post-inoculation displaying membrane vesicles (arrow). Panel F, coiled forms (arrow) observed in MS-10 cultures at 36 h post-inoculation. Scale bars represent 1 μm.