F0: A term used to designate that a particular fish is wild, or was captured from the wild and is now kept in captivity. This is used to keep track of the parental generation.

F1: First filial. A term used to designate that a particular fish is one generation away from the parental generation. In the context of the aquarium hobby, this means that a fish is one generation removed from the wild.

F2: Second filial. A term used to designate that a particular fish is two generations away from the parental generation. In the context of the aquarium hobby, this means that a fish is two generations removed from the wild.

Family: A term used in the classification of organisms (i.e., taxonomy). A family is made up of related Genera.

Fecal Coliform: A portion of the coliform bacteria group originating in the intestinal tract of warm-blooded animals that pass into the environment as feces. Fecal coliform often is used as an indicator of the bacteriological safety of a domestic water supply.

Fecal Pellets: See Pellets.

Fecal Streptococcus: The fecal streptococcus group consists of a number of species of the genus Streptococcus, such as: S. faecalis, S. faecium, S. avium, S. bovis, S. equinus, and S. gallinarum. Fecal Streptococci are typically found in the gastrointestinal tract of warm blooded animals. Due to the variation in survival rates the ratio of FC/FS should not be used as a means of differentiating human and animal sources of bacterial contamination. Fecal streptococcus colonies produced by the KF-Streptococcus broth are red. For potable water, the fecal streptococcus should be absent.

Fecundity: The number of eggs produced per female per unit time, often: per spawning season.

Fertilization: The process by which plants and animals are made capable of sexual reproduction; usually involves the joining of male and female sexual parts to produce an offspring.

Field Capacity: The amount of water a soil contains after rapid drainage has ceased. It is the water content following a period of gravity drainage without the addition of water.

Filament Chain: Living cells in a community as a series of links of trophic levels, such as primary producers, herbivores, and primary carnivores.

Filial: A term used to designate the generation or the sequence of generations following the parental generation. F0 = parental generation. See also F0, F1, & F2 above.

Filter: A device used to clean aquarium or drinking water. They come in three broad categories: mechanical, chemical, and biological.

Filter Feeder: A small animal that feeds off food suspended in the water, and collects this food with the aid of hairs, specialized mouthparts, catch nets, or other structures.

Filtration: Method of cleaning aquarium water, there are 3 basic types. "Mechanical" removes particulate material. Chemical" removal of dissolved substances by passing through a type of media, like carbon. "Biological" which is the process of changing from a harmful substance to a less harmful one, by bacteria.

Fin: A membranous appendage extending from the body of a fish or other aquatic animal, used for propelling, steering, or balancing the body in the water

Fish Catch: The volume of fish harvested over a certain amount of time or effort.

Fish Habitat: The place where fish live and grow.

Fish Productivity: The volume of fish or marine life that is produced by an area of a coral reef over a certain period of time.

Fish: Any of numerous cold-blooded aquatic vertebrates of the superclass Pisces, characteristically having fins, gills, and a streamlined body.

Fisherfolk: Men, women and children that make their living by means of fishing and harvesting marinelife from mangroves, seagrasses, coral reefs and the ocean.

Fishing Livelihood: A means of maintaining life involving the collection of fish and marinelife; income generated from collecting or harvesting fish or marinelife.

Fish Wheel: A trap-like basket made to sit along the edge of a river, and as the current turns the baskets, they scoop up migrating salmon and dump them through a shoot into a basket.

Flagellum: Long, whiplike extensions from a living cell's surface that by its motion moves the cell.

Flange: A projecting rim.

Floodplains: Frequently inundated (flooded) lands bordering rivers and streams.

Fluting: Grooves in the shaft of a column.

Foam Fractionation: See protein skimming.

Foliose Coral: A coral whose skeletal form approximates that of a broad, flattened plate.

Food Chain: An abstraction describing the network of feeding relationships – the Sequence of organisms in which each is food for the next member in the sequence.

Food Chain Efficiency: Amount of energy of some other quantity extracted from a trophic level, divided by the amount of energy produced by the next-lower trophic level.

Food Web: A network describing the feeding interactions of the species in an area, including production, consumption, decomposition, and the flow of energy.

Foraminifera: Protozoan group, individuals of which usually secrete a calcareous test; both planktonic and benthic representatives.

Founder Principle: A small colonizing population is genetically unrepresentative of the source of population.

Fragile: Delicate or easily broken, damaged or destroyed.

Free-Living: Not living in contact with another organism or not encased in a fixed burrow, retreat or case.

Freshet: An increase of water flow into an estuary during the late winter or spring, owing to increased precipitation and snow melt in the watershed.

Freshwater: Water that does not contain salt, or is not saline.

Fringing Reef: A type of coral reef that grows parallel and near to a beach shoreline.

Front: A major discontinuity separating ocean currents and water masses in any combination.

Fry: Newly hatched or born fish that is fully formed.

Fugitive Species: A species adapted to colonize newly disturbed habitats.