The quality assessment checks listed below are specific to finfish; some entries (e.g. gills) relate only to whole finfish, and others (e.g. flesh colour) relate only to fillets. The eyes, gills, scales and slime of finfish, generally deteriorate faster than the flesh. Refer also to the general quality assessment checks for all sensory criteria (opposite), which cover all seafood.
Colour of Gills
Beginning to brown
Not all finfish have red gills. Red around the gills may be blood, which can be a result of the catching method.
Translucent, very thin film
Beginning to colour (pink, yellow, brown), clot and thicken
Mucus can be washed out so care needs to be taken if using it as a quality indicator
Gut cavity (if gutted)
Well cleaned, no protruding bones, lining intact
Some yellow or green staining; some torn lining; bones beginning to protrude
If bloodline present, the blood should be bright red.
Lining can be torn during gutting.
Pupil jet-black, shiny, and well defined
Pupil becoming dull and grey
Cornea cloudy, opaque or slightly blood-stained
Finfish eyes can be damaged in numerous ways, and lesser-quality eyes do not necessarily signify poor-quality flesh.
Eye cloudiness can result from not icing the fish correctly or fish being in an ice slurry too long. Thawed finfish can have opaque or cloudy eyes as a result of ice harming the structure of eye tissue.
Lens smooth and bulging (convex)
Lens sunken (concave) or "pushed in" in the centre
Check both eyes—one may be sunken due to physical damage and the flesh may still be of higher quality. Bulging eyes can be caused by pressure changes during capture.
Firmly attached to any bones,
A few rips, bruises or blood spots; slightly dried-out, ragged edges if cut; separating from bones; slightly gaping
With fillets, also consider (where relevant) clean skin removal, size consistency, and cutting or trimming imperfections.
Variable (white, grey, pink, red, orange, etc.), but usually shiny, translucent; bloodline bright red
Bleached white, opaque; colour beginning to yellow or brown (i.e. red to brown); wrinkled surface or white cottony patches
Flesh tends to dull and yellow with age. Dry cottony patches or wrinkled product surfaces result from dehydration (known as "freezer burn" when severe).