There are 333 species of algae at the Galápagos, (35 % are endemics). Many of the algae during "El Niño" are replaced by others which can grow better in warm waters, changing the food chain.

There are 24 species of sea urchins, 28 of sea stars, 30 of sea cucumbers, about 600 of mollusca, and more than 100 of crabs inhabit in the Galapagos. You will be amazed by the colors of the Blue Sea Star Phataria Unifascialis, the shape of the Black Spiny Brittle Star Ophiocoma aethiops, the red phosphorescent skin of the Horse conch Fasciolaria Princeps and the quantity of Slate Pencil Urchins Eucidaris thouarsii.

There are 31 non-reef building corals (30% of them are endemic) and 13 reef builders. The Galápagos boasts the same amount and variety of corals as other parts of the east Pacific. The corals congregate in some areas, especially in Darwin and Wolf in more warm waters. Except that congregations, you should not expect to find large quantities of corals.

There are recorded more than 300 species of fish (17% are endemic to the Galapagos). You may expect to see big schools of Creole Fish (Gringo or Paranthias colonus), Black Striped Salema (Ojón or Xenocys jessiae), groups of Almaco Jacks (Palometa or Seriola rivoliana), Barracudas (Sphyraena idiastes), Moorish Idol (Zanclus cornutus), and dancing Rainbow Wrass (Vieja Arco Iris or Thalassoma lucasanum).

You may also encounter a Pacific Seahorse (Caballito de Mar or Hippocamous ingens) hanging in a Black Coral, a Fantail Pipefish ( Pez pipa or Doryrhamphus excisus) inside a small crevice and numerous Red-lipped Batfish (Pez Murciélago or Ogcocephalus darwini) lying in the sand, the Sanguine Frogfish (Pez Sapo or Antennatus sanguineus) changing colors due to the surrounds, sponges are more difficult to see because of their size and camouflage, and many more.

There are two species of sea lions inhabit the Galápagos; the sea lion (Lobo marino or Zalophus californianus wollebaeki) and the Fur seal ( Lobo de dos pelos or Arctocephalus galapagoensis). Take your camera, when snorkeling with them. They can bite you, so do not try to touch them.

There are also the following species as the Bride´s Whale (Balaenoptera Edeni), Sperm Whales (Physeter Macrocephalus), Killer Whales (Orcinus Orca), and others. You should try the upwelling areas, if you are looking for whales. You may have close contacts with whales when snorkeling between the islands. Draw near the whales by their rear. Make no noises or splashes.

When swimming with the Bottlenosed dolphins (Delfín nariz de botella or Tursiups truncatus) do that in front of the boats, so you could take their picture, and the small Common dolphins ( Delfín común or Delphinus delphis) likes to jump off the waves made by the boats.