Western Fisheries Science News, December 2015 | Issue 3.12 (B)
B: Rainbow trout fry experimentally exposed to IHN virus. Typical signs include darkening and exophthalmia (“popeye”) as shown by the fish in the lower portion of the photo. Other external signs may include fluid accumulation in the abdomen, trailing fecal casts, and small hemorrhages in the fins and body musculature. Image provided by USGS.