For the spice mix, grind all of the ingredients using a pestle and mortar or an electric grinder. Store in an airtight tin or box.
For the fish stock, put all the ingredients except the fish bones into a large pan, add 2¼ litres/3¾ pints water and bring to the boil. Turn down the heat and simmer gently for 20 minutes. Add the fish bones (or fish fillet) and bring back up to a simmer, skimming off any scum as it rises to the surface. Simmer for a further 20 minutes. Strain through a sieve into a clean pan and simmer a little longer, if necessary, until reduced to about 1¼ litres/2 pints. Keep warm.
For the prawn stock, heat the olive oil in a large pan over a medium heat. Add the garlic and the prawn heads and shells. Stir-fry for a couple of minutes before adding the tomato purée, salt and 300ml/10fl oz water. Cook for 10 minutes, then pass through a sieve, pushing down on the shells to extract as much of the prawn flavour as you can. Discard the shells, set the stock aside and keep warm.
For the risotto, heat 3 tablespoons of the olive oil in a large frying pan over a medium heat. Fry the shallots and garlic gently until softened. Add the rice and fry it in the oil for 2 minutes, then add the Byzantine spice mix and stir it through the rice.
Add the white wine, bring to a simmer and allow to evaporate, then add a ladle of the hot fish stock.
When this has been absorbed, add the next ladle, and continue to do so, stirring after each addition, until you have only a couple of ladlefuls left, this should take about 16-18 minutes. Add the mussels and prawn stock.
Heat the remaining tablespoon of olive oil in a frying pan until simmering and fry the red mullet strips, squid rings and tentacles and shrimps briskly for 2–3 minutes.
Season with salt and pepper. Stir the seafood into the risotto with the remaining fish stock and cook for 1-2 minutes, or until absorbed.
Stir in the butter, crab meat and parsley, and serve immediately.