Choosing a Goby
Gobies, in the family Gobiidae, are a huge family of fish found along the sandy and rocky shores of tropical, subtropical and even temperate seas. Although these fish usually don't grow to be much larger than about five inches in captivity - some species grow no larger than two inches - they are extraordinarily long-lived for reef fish. Ten years is the longest on record so far. Because of their hardiness and relative ease of care, these are among the most popular saltwater aquarium fish to keep. Neon. Elactinus oceanops is a very popular and well-known Caribbean species that inhabits reef areas, patch reefs and lagoons. Usually dark with a bright blue horizontal band running along their side, these are the famous "cleaner fishes" and are often found swimming around much larger fish or dangerous predators such as moray eels, picking off parasites and pieces of skin from these larger predatory species. Some of the large fish, such as groupers, will settle in an area, a "cleaning station" with their mouths agape while gobies dart about picking them clean. Neon gobies, therefore, require a diet rich in proteins and meats. Brine shrimp and frozen fish will do. They will also need some vegetable matter in their diets. This is often supplied by flakes and other "all purpose" foods.
Gobies are bottom-dwelling fishes that often affix themselves to the bottom by a specialized suction organ formed by its pelvic fins. (Blennies, which are often mistaken for gobies, have no such organ.) Unlike just about all other fish, gobies have no lateral line - the area along the middle of a fish's flanks that senses its position in the water. Instead, gobies have a series of sensory "pores" on the head and over the body that are connected to their nervous systems.
Gobies are relatively easy to keep and they tolerate captivity well, even though some species look as though they are highly fragile. However, gobies are shy in the close quarters of an aquarium and prefer to keep to themselves. Therefore you shouldn't keep them with overly aggressive fish since these may bully around your goby.
These species have no special water requirements other than the "normal" water-quality that is necessary to keep a reef-aquarium healthy. In fact, gobies even tolerate significant fluctuations in water quality. Nevertheless, it's not a good idea to put them through this, since they too will succumb to stress and be prone to diseases.
Varieties of Gobies
Fire. Nemateotris magnifica is a popular Indo-Pacific species. They have a pearl-colored body with fiery red markings on the tail and along their dorsal spine. A shy species, they require hiding places in your aquarium. Don't keep this goby with highly aggressive fish. They will nip at the shy fire goby's long dorsal fin. The fire goby needs a varied diet of brine shrimp or some other protein-rich food such as chopped up frozen shrimp.
Purple fire. A species closely related to the fire goby is the purple fire goby (Nematelotris decora), which comes from the western Pacific. They are usually pale gray or pink with patches of bright blue and red on its fins. The dorsal fin is also elongated, though not quite as much as that of the fire goby. Food requirements also demand a high-protein diet.
Yellow. Some of the smaller bottom-dwelling gobies are in the genus Gobiodon. The yellow goby (Gobiodon okinawae), a Pacific variety, is most at home among branches of coral. Their pelvic fins are modified to stick to rocks, ledges and coral. These fish require both meaty and vegetable foods and once adapted to your tank, usually will do very well and eat whatever they can find.