Pick up some cochineal food colouring from any major supermarket.
Pop the shrimp or prawn in a bowl pour a couple of bottles of dye cover the prawn fill it up with water to totally cover them leave them for half an hour
Dry them off on paper towel seasalt them bag them up and ready to go.
I am a painter and sculptor. All my family is related to art. Painting, Music, Sculptors, Architects, and even Florists. My father is a painter and he taught me a lot of things about painting. he taught me how to choose the paper and the dyes correctly in dependence on what you paint. When I was a child I couldn't understand how hard this thing is. I usually buy my dyes on a site that has a lot of products for people of art. Click here if you want to know what site. I also like sculpting but I am not good at it. I want to become in the future a famous artist.