[TheOldSalt]

# Acclimatization - Gradual introduction of new fish to an aquarium by equalizing the temperature and chemical parameters of their container water with that of the tank. Minimizes Stress.

# Acidic - Water with a pH less than 7.

# Acrylic - A clear plastic material used to construct aquariums. It is half the weight of glass and its refractive index is closer to that of water than glass, making it more transparent. Acrylic is more easily scratched than glass. Also called Plexiglas or Perspex.

# Actinic - A type of fluorescent bulb that gives off blue colored light often used in marine aquaria to make corals appear to glow with brilliant colors and to give the tank a "deep ocean" feel to it.

# Activated Carbon - A Filter Medium used to remove organic contaminants or residual medications from aquarium water. If used it must be renewed at regular intervals.

# Adipose Fin - A small fleshy fin located behind the dorsal fin in some fishes, e.g. certain Characins.

# Aerobic - Existing or active in the presence of free oxygen.

# Air Pump - A small electric pump, usually of the diaphragm type, used to deliver air to an aquarium.

# Air Stone - A finely perforated ceramic, glass or wooden block which diffuses air from an Air Pump into the water in the form of tiny bubbles.

# Algae - Usually unicellular plants which grow in water and attach themselves to aquarium glass, plants, rocks, decorations, etc. There are many types of Algae. An overgrowth of algae is generally considered unsightly and a nuisance (but see Aufwuchs) and can create water quality problems. Always present in water, their growth is stimulated by excessive nutrients (overfeeding fish).

# Algal Bloom - An explosive growth of Algae which discolors the water and can lead to oxygen depletion.

# Alkaline - Water with a pH greater than 7.

# Alkalinity - The ability of water to maintain a stable pH. Controlled by the amount of carbonate ions present in the water. Also called Buffering Capacity. See KH.

# Ammonia - An extremely toxic byproduct of fish metabolism and the decay of organic materials. In a fully Cycled tank the ammonia is totally converted to Nitrites and eventually Nitrates by the Bio-Filter.

# Anabantid/Anabantoid - see Labyrinth Fish.

# Anadromous - A fish that is born in fresh water then migrates to a brackish or full salt environment as it grows. Compare Catadromous.

# Anaerobic - Existing or active in the absence of free oxygen.

# Anal Fin - Fin just behind anal opening.

# Annual Fish - See Killifish.

# Anoxic - Low oxygen. More O2 than Anerobic, but not much more.

# Aquarium Salt - Additive-free salt which is used in the treatment of certain freshwater fish diseases or conditions, or added to the freshwater aquarium in very small quantities where it may be beneficial to certain types of fish. Not to be confused with marine salt which is a complex mixture of salts used in saltwater tanks to create ‘artificial’ sea water.

# Aquascaping - The artistic arrangement of plants, rocks, and driftwood to create a harmonious and aesthetically pleasing display in an aquarium. The acknowledged master of the art is the Japanese Takashi Amano. See Dutch Tank.

# Aragonite - A form of calcium carbonate which constitutes the shells of corals and other marine creatures. Crushed Aragonite sand is sometimes used as a Substrate when it is desired to raise the pH/Hardness of the tank water above its natural level, e.g. for African Lake Cichlids.

# Artemia - Artemia salina, the Brine Shrimp. See BBS.

# Astaxanthin - Carotenoid pigment supplement and antioxidant added to many foods to enhance reds, oranges, and yellows in fish. May be purchased already added to foods or separately as a powder additive.

# Aufwuchs - A German term that is used to refer to microorganisms growing on plants, rocks, driftwood, etc. If not excessive it can be decorative and provides food for some types of fish and Inverts.

# BBA - Black Beard Algae, Black Brush Algae, or Red Algae. Looks like short black, dark-green, or dark-red hairs growing on plants and decorations. High phosphate content in the water encourages its growth

# BBS - Baby Brine Shrimp. Larvae of brine shrimp, crustaceans of the genus Artemia. Cultivated as food for fry and small fishes.

# BGA - Blue-green Algae or Cyanobacteria. Aquatic bacteria that make their own food through the process of photosynthesis. Can rapidly overtake an aquarium, by spreading over everything in sheets. May smother and kill plants if not removed.

# Bio-filter - Biological Filter. Any device or Substrate which provides an attachment site for the nitrifying bacterial colony in an aquarium. See Nitrogen Cycle.

# Bio-load - Biological Load. The waste output of organisms that must be processed by the bio-filter. In a balanced system, the bio-load does not exceed the ability of the Bio-filter to process all the waste. See Cycle.

# Biofilm - A slimy matrix produced and inhabited by bacteria which enables the bacteria to adhere to a surface and carry out certain biochemical processes essential to the Nitrogen Cycle. In open aquatic environments, biofilm supports a microscopic community of various species of bacteria including nitrifying bacteria, algae, protozoa, and microscopic invertebrates. In the aquarium, biofilm covers all surfaces exposed to water, and tends to build up in the dark, undisturbed areas such as the filter intake tube and other filter parts.

# Biotope - A natural region or geographical space that presents relative uniformity of physical characteristics and animal/plant populations which inhabit it.

# Biotope Aquarium - An aquarium that is designed with the intent to reproduce an existing natural habitat or niche, in terms of its physical/visual characteristics and its naturally occurring species. See Biotope. Also see Theme.

# Black Water Extract - Home-made or commercially prepared water conditioner to create the dark, very soft and acidic water typical of Amazon Basin rivers. The chemistry and dark color is due to decaying vegetation causing high humic acid levels.

# Bloat - (a.k.a. Malawi Bloat) A potentially fatal condition caused by flagellates (protozoan parasites) proliferating in the intestines. Symptoms include loss of appetite, white, trailing feces, and bloated appearance. Common in African cichlids.

# Blood Worms - Larvae from the non-biting midge family Chironomidae. Live, frozen, or freeze-dried, they are a food item that is highly appreciated by most fish. Often used to condition fish for breeding and stimulate growth.

# Bogwood - Wood that has been preserved in a peat bog.

# Brackish - Slightly salty water typical of river estuaries and lagoons. Some fish, e.g. archer-fish, gobies, and puffers require a brackish aquarium set-up to thrive.

# Buffering Capacity - The ability of water to maintain a stable pH. Controlled by the amount of carbonate ions present in the water. Also called Alkalinity. See KH.

# CO2 - Carbon dioxide. Used in Planted Tanks to maximize plant growth.

# Canister Filter - An external Filter consisting of a sealed canister containing various Filter Media and a pump which circulates water through the media. It is attached to the aquarium by inlet and outlet hoses.

# Carbon - See Activated Carbon.

# Carnivore - A meat-eater.

# Catadromous - A fish that is born in salt water but migrates to fresh water where it grows to adulthood. Opposite of Anadromous. The common eel is one of the few examples.

# Caudal Fin - The "tail fin." In many species this is the main fin associated with propulsion.

# Characins - Loosely, a large group of fishes that includes (the mainly South American) Tetras and also some predators such as the Piranha.

# Chelate - Refers to a chemical complex where iron or some other mineral is tightly bound to an organic compound. This facilitates the uptake of iron and other trace elements by aquarium plants.

# Chloramine - Combination of Chlorine and Ammonia that is frequently added to municipal water supplies to maintain municipal water quality standards. Also prevents the establishment of Biofilm in municipal water supply lines and storage containers. It is toxic to fish and amphibians. Can be removed by treating water with a Water Conditioner that is specifically formulated to treat chloramines..

# Chlorine - Chemical element that is frequently added to municipal water supplies as a disinfectant. Prevents Biofilm establishment in municipal water supply systems. It is toxic to many fish and inverts. Less stable but a stronger disinfectant than Chloramine, it can be dissipated for aquarium use by allowing the water to stand in an open container for 24 hours, or it can be instantly removed by treating water with a standard dechlorinator.

# Cichlids - (Pronounced: SICK-lids) A huge family of Old and New World fishes whose vivid colors and interesting social behavior make them very popular with Fish-keepers.

# Clamped Fins - Posture adopted by fish where it holds its fins tightly against its body. Usually a sign of distress or sickness.

# Clutch - The deposit of eggs left by a female fish. See Spawn.

# Community Tank - An aquarium which is populated with fish of several different species, all of which are compatible with one another.

# Cory - Common abbreviation for Corydoras, a genus of small South American armored catfish with many different species that are very popular in home aquaria.

# Cycle - 1. v. To establish the nitrogen cycle in an aquatic system by promoting the establishment of nitrifying bacteria. 2. n. The Nitrogen Cycle.

# DI Water - Water that has been purified by deionization.

# DIY - Do It Yourself. Rather than purchasing an item ready-made, or having a custom item made by someone else, the DIY project involves assembling and/or constructing something from parts and materials purchased, collected, and/or fashioned by the hobbyist.

# DSB - Deep Sand Bed. A sand bed Substrate deep enough to create anoxic areas in which denitrifying bacteria can reside. Used to keep nitrate levels low in an aquarium. See Plenum.

# Daphnia - The ‘water flea,’ common crustaceans found in freshwater lakes, ponds, and slow moving streams. Cultivated or collected in the wild as fish food.

# Dead Spot - An area of poor circulation, either within the Substrate or in the Water Column.

# Denitrification - The conversion of Nitrate to nitrogen gas carried out by certain species of bacteria in Anoxic conditions.

# Diatom - Microscopic organism with a hard shell that remains after the death of the organism.

# Diatom Filter - A Filter which employs the use of diatom powder (the skeletal remains of diatoms). Used to ‘polish’ the water by filtering out particles as small as 1 micron.

# Display - To ‘show off’ by fully extending all fins and exhibiting full or special coloration, and/or special movements of the body and/or fins. Usually associated with breeding, can also be for dominance or territoriality.

# Dither fish - Fish added to an aquarium with shy or nervous fish. The dither fishes’ unconcerned behavior signals to the shy fish that it is safe to come out of hiding, and/or that it is safe to breed. Compare Target Fish.

# Diurnal - Active during the daylight hours.

# Dorsal Fin - The fin at the top of many fish. In many species of fish (such as cichlids) is distinctly separated into a spiny front portion followed by a "soft" rear portion.

# Driftwood - Wood that has been drifting or floating in water.

# Dropsy - A condition in which the body of the fish becomes swollen due to accumulated fluids. It is not a disease in itself but a symptom of various diseases which may become fatal if not treated.

# Dutch Tank - An aquarium which is designed to display plants in beautiful Aquascaped arrangements. It may or may not contain a few fish.