Goby

The most distinctive aspects of goby morphology are the fused pelvic fins that form a disc-shaped sucker. This sucker is functionally analogous to the dorsal fin sucker possessed by the remoras or the pelvic fin sucker of the lumpsuckers, but is anatomically distinct: these similarities are the product of convergent evolution. Gobies can often be seen using the sucker to adhere to rocks and corals, and in aquariums they will happily stick to glass walls of the tank, as well.

Gobies are primarily fish of shallow marine habitats including tide pools, coral reefs, and seagrass meadows; they are also very numerous in brackish water and estuarine habitats, including the lower reaches of rivers, mangrove swamps, and salt marshes. A small number of gobies (unknown exactly, but in the low hundreds) are also fully adapted to freshwater environments. These include the Asian river gobies (Rhinogobius spp.), the Australian desert goby (Chlamydogobius eremius), and the European freshwater goby Padogobius bonelli. Most gobies feed on small invertebrates, although some of the larger species eat other fish, and a few eat planktic algae.

Mudskippers

Mudskippers are highly specialized members of the family, usually ascribed to the subfamily Oxudercinae. They are able to survive for extended periods on land through a combination of behavioral and physiological adaptations, including pectoral fins that act as simple legs; the ability to breathe through their skins (like frogs); and the digging of damp burrows to avoid drying out. Mudskippers live in tidal areas, particularly on mudflats and in mangrove forests, and are only found in tropical and subtropical regions.

Reproduction

Gobies in warmer waters reach adulthood in a matter of months, while those in cooler environments may take up to two years. The total lifespan of gobies varies from a single year to up to ten years, again with the temperate species generally living longer. Some goby species live in symbiosis with burrowing shrimps. The shrimp maintains a burrow in the sand in which both the shrimp and the goby live. The shrimp has poor eyesight compared to the goby, but if it sees or feels the goby suddenly swim into the burrow, it will follow. The goby and shrimp keep in contact with each other, the shrimp using its antennae, and the goby flicking the shrimp with its tail when alarmed. These gobies are thus sometimes known as watchmen or prawn gobies. Each party gains from this relationship: the shrimp gets a warning of approaching danger, and the goby gets a safe home and a place to lay its eggs. Only the alpha male and female reproduce, other fish in colony eat sparingly to resist being eaten by the alpha male or female. This way only the largest and fittest are able to reproduce.

Another example of symbiosis is demonstrated by the neon gobies (Elacatinus spp.). These gobies are known as "cleaner gobies", and remove parasites from the skin, fins, mouth, and gills of a wide variety of large fish. The most remarkable aspect of this symbiosis is that many of the fish that visit the gobies' cleaning stations would otherwise treat such small fish as food (for example, groupers and snappers). Again, this is a relationship where both parties gain: the gobies get a continual supply of food as bigger fish visit their cleaning stations, and the bigger fish leave the cleaning stations healthier than they were when they arrived.

In aquariums

Several species of gobies are kept in aquariums. Most captive gobies are species from saltwater, and make excellent additions to healthy reef or fish-only aquariums. Perhaps the most popular is the small but colorful neon goby. Most gobies stay toward the lower portion of the aquarium, hiding in the rockwork, but some species (most notably the shrimp gobies) prefer to dig themselves little burrows. Potential keepers of these striking fish should provide them with a fine grained substrate to prevent damage to their delicate undersides. Commonly kept saltwater species include the engineer goby, Randall's shrimp goby, and watchman goby. The bumblebee gobies from the genus Brachygobius are perhaps the most widely traded freshwater species, being small, colorful, and easy to care for. They need tropical, hard and alkaline freshwater or slightly brackish conditions to do well. Gobies are generally peaceful towards their tankmates, though territorial among themselves. Since most are small and few are predatory toward other fishes, they usually make good community fishes. Typically, the main problem with gobies is feeding them: with a few exceptions, the small species kept in aquariums prefer live on frozen foods rather than flake, and they are not very good at competing with active species such as cichlids. Another problem is that it is very common for them to jump out of the tank so having a tight fitting lid is a must. It is often recommended that gobies be kept on their own or with peaceful surface dwelling species such as halfbeaks and guppies.

See also

References

External links

* Category:Symbiosis