The invention provides methods for producing biofuel from algae, that use fish which have a high capacity of producing and/or accumulating lipids to harvest algae from an algal culture. The invention also provides methods for growing fish that result in a high lipid content. The invention also provides methods for creating fish that have a high capacity of producing and accumulating lipids by breeding and/or recombinant DNA techniques. Also included are transgenic fish that have a higher lipid content than wild-type fish.