How do you know if haddock is bad?
Some common traits of bad fish are a slimy, milky flesh (a thick, slippery coating) and a fishy smell. This is hard because fish is smelly and slimy by nature, but these traits become much more pronounced when fish has gone bad. Fresh fillets should glisten like they came out of water.
How can you tell if fish is spoiled?
Look for firm, shiny flesh: The flesh of the fish should bounce back on touching it. The skin has a natural metallic glow and should not look dull. The surface of the skin must be tight and the scales might be tightly attached. Cracked skin or loose scales could be signs of rotting fish.