Ten fish varieties you mightn't know but should try

• Top 10 fish to try, and how to cook them
• International eco labels reach restaurant menus

It's early morning at the Sydney Fish Market and the buyers are locked in a Dutch auction for seafood that seems more like a game of chicken. Imagine a concrete basketball stadium where the fish are the players and the fishmongers sit in the stands. On a massive screen the price starts high then quickly counts down while two giant clocks tick backwards. Second-guessing each other, the buyers press a button to stop the clock. Press too soon and they pay too much. Press too late and their competitors get the fish. The stars of the auction are Australia's most-loved fish. Flathead sell for about $7 a kilogram. Those that are left, the fish-market wallflowers, are virtually unheard of outside industry circles. They have names such as eastern Australian salmon, sea mullet and school whiting. These are sustainable fish species that are native to our seas, have some of the highest levels of healthy omega-3 oils, and are some of the tastiest fish in the country, yet they struggle to reach prices above $4 a kilogram wholesale.

On a box of ice sits a clutch of gleaming eastern Australian salmon. Eyes bright and scales glistening, today they went for just $3.50 a kilo. "You know, this is a beautiful fish," says Gus Dannoun, supply manager at the Sydney Fish Market. "In New Zealand they call it kahawai and they love it. In Polynesia they marinate it in lime juice and coconut - ceviche. It's delicious. Here it's used a lot for lobster bait." Dannoun scans the floor and comes to a roundish plate-sized fish that seems to have silver metallic skin. "Mirror Dory," he says. "If you like John Dory you'll love Mirror Dory but it's only a quarter of the price."

We pass King George Whiting's lesser-loved cousin the eastern school whiting, a small sandy-coloured fish. It too is sold at bargain prices yet, Dannoun says, is a delicious little fish. "When filleted, it's sold at pubs and clubs as 'whiting' and no one bats an eyelid."

Dannoun says Australians are very picky when it comes to eating fish, choosing just a handful of species which in turn puts pressure on the prices we pay. For example, just 10 years ago flathead fillets were about $12 to $15 a kilogram retail. Today they hover around the $40 a kilogram mark with some reports of flathead reaching up to $55 a kilogram. It is important to note that, from a whole fish such as flathead, bought at about $7 a kilogram wholesale, only 25 per cent of that fish can be turned into saleable flesh, so the wholesale price becomes $28 a kilogram for fillets. Add on overheads such as labour, energy and transport, plus profit margin, and the price you pay edges up.

"I don't want to pay rock-star prices for rock-star fish," says chef Paul Wilson, whose legendary soft egg and truffled polenta created at Radii at the Park Hyatt in Melbourne is still being talked about 15 years later. Now creative director at Bondi Beach restaurant Icebergs, he's introducing his clientele to more flavoursome but lesser-loved fish. "It's the Mediterranean approach to seafood," says the English-born chef. "You buy fish from day boats. You cut out a whole lot of middle men and end up with a fresher, better product.

"There are myriad different flavours from the different species because of where they are caught and what they eat.

"The lesser-loved fish have more oil content, which means more 0mega-3, and have eaten more exotic foods such as sea grass, shellfish and other fish.''

Flathead are one of the targeted species for the fleet at Lakes Entrance in Victoria's east Gippsland, with most of the catch heading to Sydney and Melbourne. What is harder to sell is a lot of silver dory, butterfly gurnard and the funny-looking boarfish - with spines on its dorsal and a snout like an echidna it is perhaps one of the nation's least glamorous fish. At Lakes Entrance fresh fish shop, Omega 3, boarfish are stripped of their skin and bones and the fillet baptised in batter and hot oil and sold with chips. Sweet, moist, soft, and with a lovely texture, boarfish is superior to shark, sold as flake, which is normally served with chips in Victoria. At Omega 3, I watched customers walk into the shop, ask about boarfish, then move on to the adjoining supermarket to buy inferior-tasting, more expensive imported farmed fish.

"Boarfish are local, delicious and sustainable," says Dale Sumner, manager of the Lakes Entrance Fisherman's Co-Operative. "Our fisherman find it really frustrating that they are landing all this delicious fish and are not being paid well for it. We are really proud of sustainable fishery but we are not getting a premium for it."

He presents a luderick, a native fish caught in the Gippsland Lakes fishery, a mix of fresh and salty water. Taken home, cleaned, filleted, dusted in semolina and gently pan-fried in a little olive oil, it is perhaps one of the most delicious fishes I have tasted. Salty yet sweet, tasting of the sea but with touches of the green earthy flavour of fresh water weed. Its flesh sells for less than $10 a kilogram. Another species the fish co-op finds hard to move is butterfly gurnard, a pinkish-red fish with spikes on its head and amazing butterfly wing-like pectoral fins. Filleted, it's moist with nice chunky flesh like a small cod. Lakes Entrance chef Erik Monteith from The Boathouse, a modern restaurant overlooking the town's fishing fleet, grew up in seafood-mad Sweden and loves local gurnard. "It's like flathead in that it is easy to overcook, but it has sweet flesh and tastes wonderfully of the sea."

Flavour in fish, particularly strong flavour, is not something that Australians are generally good at. For generations, most of us have been raised on the whitest, softest and most gentle-tasting fish. Give us something with flavour and we baulk. Sydney chef Griff Pamment proved this late last year when he opened Luxe in the upmarket suburb of Woollahra and served the succulently oily sea mullet just cooked on the hot grill. It was sent back to be cooked for longer. "At that point it is overcooked and turns to mush," he says. Pamment also served albacore tuna, blue fin tuna's leaner cousin. "I was being told that people thought the chicken was tasting funny. Albacore is a really good and affordable fish."

Wilson says: "The problem is people like fish that doesn't taste like fish. Which is why you have to know how to cook it. We need to understand the flavour of each species and then work out what goes with it. These fish with larger flavours go really well with tomato-based sauces and spices. We've got some work to understand our lesser-loved fish."

Back in the Sydney Fish Market, Dannoun points to a box of blue mackerel and sea mullet and says: "These fish contain some of the highest amounts of beneficial omega-3 oils. They are delicious when cooked the right way but many people, even in the industry, just use them as bait."