G - Aquarium and Fish Dictionary

GAC
Gammarus
Gang Valve
GH - General Hardness
Genital Papilla
Genus
GFCI
GPD
GPH
Gills
Gonopodium
Gorgonian
Gravid Spot
Green Water
Grindal Worm

Aquarium Fish Definition and Glossary

GAC :: abbreviation for Granular Activated Carbon.
Gammarus :: a freshwater amphipod that is used to feed fish.
Gangvalve :: a valve that is used with multiple air lines to direct and regulate air flow to each of the tubes.
GH :: abbreviation for General Hardness. This is a measurement for the total amount of dissolve minerals in your tank.
Genital Papilla :: is the tube through which the sperm and eggs pass on fish and can only usually be seen during breeding. Angelfish has a genital papilla.
Genus :: is a taxonomic group of similar organisms that has one or more species. For example, for the freshwater angelfish, Pterophyllum scalare, Pterophyllum is the genus and scalare is the species.
GFCI :: abbreviation for Ground Fault Circuit Interrupter. A GFCI outlet is a safety device that will prevent you from getting shocked or electrocuted. When the circuit detects a difference in electrical flow through the outlet it will trip the circuit, preventing serious damage to the aquarist from happening. These are a must have around aquariums. It's also a good idea to always turn off the electricity to the tank before working in it.
GPD :: abbreviation for Gallons Per Dat. This term is often used when referring to how many gallons of water a reverse osmosis filter or RO/DI filter can produce in a day.
GPH :: abbreviation for Gallons Per Hour. This term is used when referring to filter turnover or water turn over within an aquarium.
Gills :: are used by fish to extract gases (oxygen) from the water. Also see: Respiration.
Gonopodium :: is a modified anal fin for reproductive purposes. Also see: Livebearer Fish.
Gorgonian :: is an octocoral species that can take on various forms such as branchlike, encrusting or whiplike. Some species contain zooxanthellae, while other gorgonian species do not.
Gravid Spot :: is a term usually encountered when dealing with the freshwater livebearing fish. Gravid simply means carrying and developing eggs. The gravid spot is usually a dark spot located near the anal vent and is often easily seen in fishes such as the guppy and swordtails. In Mollies and platies it may be more difficult to see, especially in darker colored fish.
Green Water :: the result of an algae bloom, green water can be unattractive to look at but shouldn't harm the fish. The amount of dissolved nutrients in the tank are the primary cause of green water. For ideas on how to correct green cloudy water, please read cloudy aquarium water.
Grindal Worm :: sometimes called dwarf white worms, these are white worms that reach about 1/2 an inch in size and they are used to feed smaller fish species and fry.