This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
"Fish in stream" appearance is seen in? 
Select and explain. 
A. Hemophilus ducreyi, B. Proteus, C. Mycoplasma, D. V. Cholerae
D: V. Cholerae
Answer: D: V. Cholerae 
Explanation: Ref: Ananthnarayan and Paniker's Textbook of Microbiology, 8th ed. pg. 302* In stained films of mucus flakes from acute cholera cases, the vibrios are seen arranged in parallel rows, described by Koch as the fish in stream' appearance.* "School of Fish" appearance is seen in H. ducreyi.* Vibrios are Gram-negative, rigid, curved rods that are actively motile by means of a polar flagellum. The name 'vibrio' is derived from the characteristic vibratory motility/darting motility* The cholera vibrio is a short, curved, cylindrical rod, about 1.5x0.2-0.4mm in size, with rounded or slightly pointed ends. The cell is typically comma shaped.* Aside from V. cholera, darting motility is also seen in Campylobacter.