Delfín es el nombre común de los mamíferos acuáticos dentro del infraorden Cetacea. El término delfín generalmente se refiere a las familias existentes Delphinidae, Platanistidae (los delfines de río de la India), llamadas Iniidae y Pontoporiidae, y los extintos Lipotidae. Hay 40 especies existentes nombradas como delfines.

Las tortugas son reptiles del orden Chelonia o Testudines. Se caracterizan por un caparazón óseo o cartilaginoso, desarrollado a partir de sus costillas, que actúa como escudo. Los testudines incluyen tanto especies existentes (vivas) como extintas. Sus primeros miembros conocidos datan del Jurásico Medio.

Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles.

Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen), usually hidden entirely under the thorax. They live in all the world's oceans, in fresh water, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers.

Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea. Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish are also known as Asteroids due to being in the class Asteroidea.

Any of approximately 34,000 species of vertebrate animals (phylum Chordata) found in the fresh and salt waters of the world. Living species range from the primitive jawless lampreys and hagfishes through the cartilaginous sharks, skates, and rays to the abundant and diverse bony fishes.

Sea snakes, or coral reef snakes, are a subfamily of venomous elapid snakes, the Hydrophiinae, that inhabit marine environments for most or all of their lives. Most are extensively adapted to a fully aquatic life and are unable to move on land, except for the genus Laticauda, which has limited land movement.

Octopus are soft-bodied, eight-limbed molluscs of the order Octopoda. The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beak, with its mouth at the center point of the eight limbs.

Coastal Birds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations.

Sea Tree, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. Seaweed species such as kelps provide essential nursery habitat for fisheries and other marine species and thus protect food sources; other species, such as planktonic algae, play a vital role in capturing carbon, producing up to 50% of Earth's oxygen.