During the last two decades there has been a tremendous growth in the production of intensively farmed fish. This growth has been accompanied by a substantial reduction in prices. As this enhances the competitiveness of farmed fish, concerns are often raised with respect to the market impact of new aquaculture species. Of particular interest is the relationship to wild species in the output market as well as in the input market because of the demand for feed. In this paper we investigate what we know about market interactions based on two simple market models, where the difference between the two models is whether the competing product is wild-caught seafood or a traditionally produced product.