Depending on the size of the sea-horses, Judy Cisneros' Patchwork Pizzazz method might work. She cuts rectangles and squares of the theme fabric (61/2, 121/2 sq. and 61/2x121/2 rectangles, if I remember rightly, and uses the remaining fabric along with her other fabric choices for nine-patches and occasional fill-in strips. It is straightforward (literally!) and you still end up with something original and personal. Can't lay my hands on the book right now, so please check those sizes.