It is an endemic species of Brazil, lives in dark waters in the Amazon river basin, and is found among roots and rock crevices. It is peaceful to live together with other individuals. It has parental care for the offspring and produces a mucus to nourish the fry in the first days of life. It feeds on insects, insect larvae, plankton and eventually fruits.

It is an animal, from the same group of starfishes and sea cucumbers, the Echinoderms. It is found in the Mediterranean Sea and the Indo-Pacific Ocean, from the Red Sea to the islands of the South Pacific and Japan. It is benthic, that is, it lives associated with the marine substrate, at depths between 0 and 70 m. It is usually associated with coral reef environments with many dead corals, feeding on algae that grow there. Individuals have external fertilization (they release their gametes in the water) and can measure up to 60 cm in length.

It is a species found in tropical waters of the Atlantic Ocean, from the United States to Brazil. It lives on rocky reefs, on sandy or muddy substrates and on seagrass beds, at depths of up to 50 m. It can occur in large numbers, with up to 15 individuals being found per square meter. The individuals are mostly herbivores, feeding on seaweed, and can reach up to 11 cm in length.

It lives in South America, in rocky crevices between roots, in the Amazon, Negro and Solimões rivers. It usually lives in shoals, but during the reproductive period it becomes territorial. They feed on planktonic invertebrates, insects and insect larvae.

It lives in coral reefs in the Indo-Pacific, at a depth of 25 to 70 meters. Its maximum length is 9 cm. It lives in rougher waters, always looking for zooplankton (copepods and crustacean larvae) to feed on. In this species, monogamy is also observed and the males take care of the eggs and young (fry). When it feels threatened, it tends to hide, so it's important to have dens available in the tank.

Usually found in muddy regions and in brackish waters, mangroves and estuaries. They are fish capable of breathing air, so they can go in search of food by jumping or walking on mud and/or sand. Its diet consists of crabs, insects, among others arthropods and white mangroves.

Found in Mexico, this species inhabits small to large rivers, and rocky and sandy bottoms. Their diet is based on worms, insects and crustaceans. There are two variations of this species, the ones that live on the surface, so they have color and good eyesight; and those who inhabit caves, who throughout evolution have lost their vision and pigmentation (therefore, they are albino), as they are indifferent characteristics in the dark environment in which they live. Richard Borowsky did a study where, from genetic crosses, he managed to produce individuals with rudimentary “eyes”, and, in one of the crosses, 40% of the pups were born with sight. "If you were to hybridize two separate populations of blind cave fish and place them in a place with light, I suspect that [natural] selection pressure would be enough to restore sight to the entire population in a relatively short time, less than a hundred generations", said the researcher in an interview with Folha. Source: https://www1.folha.uol.com.br/fsp/ciencia/fe1201200801.htm

It lives in the Western Atlantic, hidden in coral reefs, at a depth of up to 25 meters. It feeds on algae and sponges. It can reach 7 cm.

Found in the Indo-West Pacific, they can reach 115 meters deep. It lives on rocky bottoms and among coral reefs, feeding on fish and crustaceans. They can reach 20 cm in length. It travels long distances and lives in small groups. Remembering that the species of lionfish that became known for starting to invade the Brazilian coast at the end of 2021 is Pterois volitans.

Found throughout Brazil, in rivers, streams and lakes. It feeds on seeds, fruits, terrestrial insects, scales, aquatic vegetables, spawns and other fish. It is kind of small, its maximum size is 12 cm.

Not much is known about this species. They are found in the Pacific, in coral reefs, tide pools and seagrass beds. It swims at a depth of up to 12 meters and can reach 72 cm in length. Its reproduction is oviparous. There are no laws restricting fishing for this animal, they are greatly affected by dynamite fishing.

It is a common species in the Indo-Pacific sea, often found in the Great Barrier Reef of Australia, at a depth of 1 to 100 meters. Juveniles can be seen in more protected areas, such as holes in reefs, they feed on sponges, corals and other organisms that settle in this region. They are very popular in aquarism for their coloration that draws attention, juveniles are black with light blue and white curves and when they become adults there is a color change, with yellow and blue horizontal lines. Their maximum size can be 40 cm when adults.