Soak the washed clams in plenty of cold water for a few hours. Shell the prawn tails remove the black intestine thread then wash and dry. Clean the small squids from the entrails and the outside skin, wash, dry and chop them into small bits.Wash, dry and mince the parsley, peel the clove of garlic and crush it, then wash and finely slice the shallot. Blanch the tomatoes in boiling water, deseed them and remove skin and their own juice and chop coarsely.Drain the clams, put them in a saucepan, add the garlic, a bit of chopped parsley, the white wine and a tbsp of oil; allow the clams to open over a moderate heat, cover the saucepan with a lid and toss it from time to time.Remove the pan from the heat, shell the clams and place them in a bowl removing the ones that did not open. Filter the cooking juice and set aside. Pour some oil saucepan with the shallot and the tip of red chilli and fry until soft but not golden; add the squids and the prawn tails and brown for 2-3 minutes, stirring with a wooden spoon.Season with salt and set aside. In the same saucepan once salted, place the tomatoes and cook for 7-8 minutes. Add to the tomatoes the prawn tails and the squids set aside, the clams, a few tbsp of the filtered cooking liquid and keep cooking for another couple of minutes.Finally Sprinkle the with the remaining parsley. Cook the pasta in a saucepan with plenty of boiling salted water. Drain it al dente, mix it with the fish ragù and serve warm.