There are two main groups of fish; Flat and Round.
Sub-groups of these fish groups are: Oily, White and Shellfish.
What to look for when buying fish:
Whole Fish
| Feature | Fresh Fish ✅ | Not Fresh ❌ |
|---|---|---|
| Eyes | Clear, bright, slightly bulging | Cloudy, dull, sunken |
| Skin & scales | Shiny, metallic; scales tight | Dull, patchy; scales loose |
| Gills | Rich red or pink; moist | Brown, faded, or slimy |
| Smell | Clean, briny, cucumber-like | Sour, ammonia, strong “fishy” |
| Flesh | Firm; springs back when pressed | Soft; leaves indentation |
| Belly | Intact, smooth | Burst or swollen |
Fish Fillets
| Feature | Fresh Fillet ✅ | Not Fresh ❌ |
|---|---|---|
| Appearance | Moist, shiny, translucent flesh | Dull, dry, opaque flesh |
| Color | Consistent, vibrant (white, pink, red) | Brown edges, yellow patches, faded |
| Texture | Firm, resilient, holds shape | Mushy, watery, breaks apart |
| Smell | Clean, ocean-like, cucumber scent | Strong fishy, sour, ammonia odor |
| Moisture | Light natural liquid | Milky/cloudy puddles, excess liquid |
Smoked Fish
| Feature | Good Smoked Fish ✅ | Not Good ❌ |
|---|---|---|
| Appearance | Even color, glossy surface, intact slices | Uneven color, cracks, dull surface |
| Texture | Firm, slightly moist, holds shape | Dry, crumbly, or overly soft |
| Smell | Pleasant smoky aroma | Sour, rancid, or ammonia odor |
| Moisture | Slightly moist, not sticky | Slimy, sticky, excessive liquid |
| Packaging | Vacuum-sealed, clear date label | Damaged seal, missing/expired date |
Frozen Fish
| Feature | Good Frozen Fish ✅ | Not Good ❌ |
|---|---|---|
| Appearance | Natural color, no fading or yellowing | Discolored, dull, yellow patches |
| Ice Crystals | Small, even crystals | Large ice chunks, frost burn |
| Texture | Solid, firm when frozen | Soft, bendable, or watery |
| Packaging | Vacuum-sealed, intact, no excess air | Damaged, torn, or loose packaging |
| Smell | Little to no odor when frozen | Strong fishy or sour smell |
Portion Size
Allow 100g of fish that is off the bone and 200-300g for fish on the bone per person for an average portion size.
Fish Cuts
| Cut | Description | Best Uses |
|---|---|---|
| Whole Fish | Entire fish, cleaned and gutted | Roasting, steaming, grilling |
| Fillet | Boneless side of fish; can be whole, V-cut, or J-cut | Pan-frying, baking, poaching |
| Steak | Cross-section cut through the backbone | Grilling, broiling, pan-searing |
| Loin | Thick, prime section from large fish (e.g., tuna) | Searing, sushi, sashimi |
| Supreme | Premium fillet cut, skinless and boneless | Fine dining, delicate sauces |
| Goujons | Thin strips of fillet | Deep-frying, fish fingers |
| Paupiette | Thin fillet rolled around stuffing | Baking, steaming |
| Butterfly | Fillet cut and opened like wings | Grilling, stuffing |
| Collar | Cut near the gills and pectoral fins | Grilling, roasting (rich flavor) |
| Cheeks | Small, tender muscles from the head | Pan-frying, sautéing |
| Darnes | Thick steak cut across the backbone, usually from round fish | Grilling, pan-frying, poaching |
| Tronçons | Large steak cut from big fish, often bone-in | Braising, roasting, court bouillon |
| Délice | Boneless fillet folded into a neat portion | Elegant plating, sauced dishes |
| Plaited (en tresse) | Two or more fillets braided together | Showpiece dishes, baking, steaming |
Cooking Methods
As quite a lot of fish (and seafood) can be quite delicate, choosing the correct cooking method to ensure it doesn't fall apart is paramount.
Shallow frying, deep frying, stir frying, grilling, poaching, sous vide, boiling, roasting, steaming, baking, braising and stewing are some of the main ways you can cook fish and seafood.
Shellfish
Invertebrates
Both lobsters and crabs are invertebrates meaning they do not have an internal skeleton.
Molluscs - mussels and scallops have a hinged double shell and things like winkles/whelks have a single spiral shell.
Cephalopods - In seafood, a cephalopod refers to marine mollusks like squid, octopus, cuttlefish, and nautilus. Although things like Octopus do not have a shell, squid have an internal 'shell' called a pen and cuttlefish have an internal shell called the cuttlebone.
Crustaceans - A crustacean is an aquatic arthropod with a hard exoskeleton, jointed legs, and two pairs of antennae. Common seafood examples include crabs, lobsters, shrimp, prawns, and crayfish
| Feature | Crustaceans (crab, lobster, shrimp) |
Cephalopods (squid, octopus, cuttlefish) |
Molluscs (clams, mussels, oysters, scallops) |
|---|---|---|---|
| Skeleton | Hard external exoskeleton (chitin + calcium) | Soft body; internal supports (pen/cuttlebone); external shell only in nautilus | Hard external shell (single or two hinged valves) |
| Limbs / appendages | Jointed legs, often claws | Tentacles/arms with suckers | No limbs; muscular foot for movement/digging |
| Nervous system | Relatively simple, less centralized | Highly developed; large brain and complex behavior | Simple; less mobility-focused |
| Defense | Hard shell; claws | Ink release; camouflage; jet escape | Shell closure; burrowing |
| Common seafood use | Crab, lobster, shrimp, crayfish | Squid (calamari), octopus, cuttlefish | Clams, mussels, oysters, scallops; also whelks/razor clams |
| Texture & flavour | Sweet, firm, sometimes buttery | Mild, slightly sweet; tender when cooked well | Briny; chewy to tender; strong “oceanic” character |
Grilling
To me a grill is something you would put something under to toast (or grill) something like melting cheese on toast.
Whereas more technically, grilling means exposing food to direct, dry heat - usually from below (charcoal, gas flame, or electric element) - to cook it quickly and give it a smoky, charred flavour.
It also all depends on what country you are in/from as things can mean one thing in the UK for example with a different meaning in the USA!
| Term | UK meaning | US meaning |
|---|---|---|
| Grilling | Direct heat from above (oven grill or eye-level grill) | Direct heat from below (outdoor grill/barbecue) |
| Broiling | Rarely used; typically just called “grilling” | Direct heat from above (oven broiler) |
| Barbecuing | Slow cooking outdoors over charcoal or wood | Often interchangeable with grilling; any outdoor cooking over flame |
| Grill (noun) | Top oven element or separate eye-level grill unit | Metal grate over a flame/heat source (gas, charcoal) |
| Salamander grill | Professional overhead grill used in restaurants | Same term; primarily commercial/pro kitchens |
From the above chart when I've been 'grilling' melted cheese on toast, the Americans would say it has been broiled - you learn something new every day!