reddish

Non-pathogen related...
Ceratonova shasta
Fish liver showing dark red lesions due to C. shasta infection.
Ceratonova shasta
Fish intestine showing swelling and pale lesions due to C. shasta infection
IHN virus
Hemorrhaged swim bladder caused by IHN virus
Aeromonas salmonicid...
Red patches caused by Aeromonas infection.
Copepods (sea lice)
Sealice and feeding scars on skin of trout.
Copepods (sea lice)
Sealice and feeding scars on skin of salmon.
Tumor-like lumps
Tumors on lips of adult spring Chinook salmon.
Bacteria
Bacterial lesion on side of trout.
Strawberry disease
Red patches known as "strawberry disease".
Aeromonas salmonicid...
Red patches (furunculosis) caused by Aeromonas infection.
Bacteria
Bacterial lesion on tail of carp.
Bacteria
Large carp with lesion on tail.
Bacteria
Goldfish displaying red patch on face due to bacterial infection.
Bacteria
Goldfish displaying red patch on face due to bacterial infection.
Ceratonova shasta
Fish liver showing areas of necrosis and damage due to systemic Ceratomyxa shasta infection.