General Morphology body structure body measurements head structure head measurements gill structure fin types tail types Applications gill counts scale counts fin counts Specific Morphology Clupeid Cyprinoid Cyprinoid top view Pleurectinoid Pleurectinoid head Salmonid Salmonid head Acipenserid Acipenserid head Percid Silurid Silurid head Mussel Mussel exterior Oyster Oyster exterior Clam Clam exterior Penaeidea Reptantia Reptantia ventral view