Heat the chicken stock and seafood stock in a medium saucepan over medium heat. Add the saffron then bring to a simmer for about 10 minutes.
Heat a 16-inch paella pan or large enameled cast-iron casserole dish over medium heat, add the olive oil and heat through. Add the onion and sauté, stirring occasionally, until tender, about 5 minutes. Add the garlic, tomato and paprika and cook for an additional minute, stirring constantly.
Add the rice and stir to coat in the oil, letting it cook for about a minute. Add the warmed stock and stir to combine and evenly spread the rice out in the pan.
Cook, without stirring, but rotating the pan frequently, until half the liquid has been absorbed, about 15 minutes.
Season the monkfish on all sides with salt and pepper. Reduce the heat to medium-low then nestle the chorizo, monkfish and shrimp into the rice.
Cover with aluminum foil and cook for 5 minutes. Add the mussels and clams with the hinge-side down as well as the squid, and peas. Cover again and cook until the clams and mussels open, about and additional 8 minutes.
Remove from heat and let stand an additional 10 minutes.
Garnish with parsley and lemon then serve immediately.