Gobies

Stiphodon, Sicyopus and Lentipes gobies come from fast, clear streams, and most are rated difficult. Stiphodon gobies graze algae and biofilm off the rocks. Lentipes gobies graze too and also take small frozen and live food. Sicyopus gobies are micro-predators that ignore algae and need small frozen and live food such as cyclops, baby brine shrimp and bloodworm. The grazers starve quietly in a new tank, which has nothing for them to eat. Give them a mature tank with strong flow, cool clean water and light enough to grow algae, and they are among the most colorful freshwater fish there are. The Rhinogobius gobies want it cooler still, down to 61°F (16°C).

The peacock gudgeon is the community goby, a peaceful 3 inch (7.5 cm) fish for a 20 gallon (75 liter) tank that takes frozen food readily. The desert goby is the one freshwater goby rated beginner. Empire and carnival gudgeons sit midwater. The blue neon carnival gudgeon is marked schooling, and the empire gudgeon is marked social and kept as a group. The purple spotted gudgeon grows to 7.9 inches (20 cm) and eats anything small enough.

The bumblebee goby is sold everywhere and rated difficult here for one reason: it eats live and frozen food only and starves on flake. The knight goby wants the same brackish water. The other bumblebee gobies are marked medium. The freshwater, sabanus and mini bumblebee gobies need no salt at all. The violet goby is a 21.7 inch (55 cm) sand-sifter that lists a 119 gallon (450 liter) brackish tank. The Indian mudskipper needs land as well as water. None of them belongs in a standard freshwater community.

Firefish and the dartfish hover in open water rather than sitting on the bottom, dart into a hole when startled, and jump. They are rated easy and reef safe, which makes them favorites for a first reef, as long as the tank has a lid. The firefish and purple firefish are marked mostly peaceful because they fight their own kind, and the rest are peaceful. Firefish pair or go singly; the dartfish prefer a small group.

A shrimp goby and a pistol shrimp share a burrow that the shrimp digs and the goby guards. The shrimp is nearly blind and keeps an antenna on the goby's tail; a flick sends both into the hole. The pink-spotted watchman goby is marked easy at 3.9 inches (10 cm) for 30 gallons (115 liters) and pairs with the tiger pistol shrimp, as do the orange-spot prawn goby and the pinkbar goby at 4.3 inches (11 cm). Randall's prawn goby is the same group at 4.7 inches (12 cm), marked medium. The yasha goby and the hi-fin red banded goby are 2.4 inches (6 cm) for 15 to 20 gallons (57 to 75 liters). Both usually pair with Randall's pistol shrimp. Buy the goby and the shrimp together and give them a sand bed at least 2 inches (5 cm) deep.

Most Elacatinus gobies pick parasites off larger fish, which hold still and open their gills for them. All of them are marked easy, peaceful and reef safe at 1.6 to 2 inches (4 to 5 cm) for 11 gallons (40 liters); the sharknose goby lists 13 gallons (50 liters). The barber goby is the Brazilian one. The barsnout, broadstripe, neon and sharknose gobies are the Caribbean cleaners, and the red head goby is the eastern Pacific one. The yellowline sponge goby lives in tube sponges and does not run a cleaning station. A pair spawns in a shell or a bit of pipe, and the fry are among the few marine fish raised at home.