External & Internal Signs

Clinical Signs
Clinical signs of Streptococcosis include fish are lethargic, anorexia and present with external signs (darkening of skin, bilateral exophthalmia and loss of orientation). However, L. garvieae infection results in a Hemorrhagic Septicemia with characteristic Hemorrhagic Enteritis, whereas fish infected with Streptoccoccus iniae have Meningitis and Panophthalmitis.

Abnormal swimming behaviour
Affected fish can be lethargic, exhibit a spiral motion or have disorientated swimming behaviour.

Eye lesions
Unilateral or bilateral exophthalmia (“popeye”), clouding of the cornea and eye haemorrhage are common clinical signs in infected fish.

Skin lesions
Darkened skin is common in infected fish. Discrete petechial haemorrhage may be present all over the body surface but especially at the bases of fins and tail.

Internal septicaemia
Spleen and kidney appear enlarged, the liver is haemorrhagic and ascites can be present in the abdominal cavity.