In a small bowl, combine the sweet paprika, turmeric, sumac, cumin, onion salt and Himalayan salt to make the spice mix. Set aside until required.
Clean and debeard the mussels. If any mussels are opened, tap them lightly on a hard surface. If they don't close, discard them. Place the mussels and wine in a large, heavy based saucepan, covering the pot with a lid. Cook the mussels for about 3-4 minutes over medium heat, giving the pot a shake from time to time. The mussels are cooked when they've opened up. Be sure to discard any that don't open. Strain into a colander reserving the juices from the mussels. When cooled remove the mussel meat from their shells, keeping a few as they are for garnish.
In a separate saucepan pour 1/3 of the roasted vine tomato sauce into the pot. Lightly coat the fish fillets with the spice mixture and gently add them to the tomato mixture, nestling the fish pieces nicely on the base. Coat with the remaining tomato sauce and the reserve mussel liquid. Cover with a lid and cook over a gentle medium heat for 8-15 minutes until the fish is cooked through (this will depend on the type of fish you are using and the thickness of the fish).
During the last 2 minutes of cooking add the cooked mussels and coriander, gently stir being extra careful not to break up the fish fillets. Taste and season if necessary.
Serve in deep soup bowls with a dollop of harissa and crusty sour-dough.