Gravel-type consisting of small, rounded grains. Commonly-used as a substrate in aquaria.
Glossary: pea gravel
A compressed accumulation of partially-decomposed, chiefly vegetable matter typically found in certain marshes, bogs, and peat swamp forests throughout the world. It forms via breakdown of various plants and other organic materials in water when full decomposition is prevented due to localised acidic, anaerobic conditions. As a result of this somewhat specific nature the organisms […]
Glossary: peat swamp forest
Type of tropical moist forest lying over a thick bed of acidic peat, over 60% of which occur in Indonesia and Malaysia. Typically contain water with very low pH (<4.0) that is stained brown due to the release of various organic compounds from the decaying peat and thus often referred to as blackwater swamps. Usually […]
Glossary: pecking order
Type of social hierarchy in which individuals within a given group or population are ranked by behavioural and/or physical dominance. Sometimes referred to as a dominance hierarchy.
Shaped like or resembling a comb; possessing projections that resemble the teeth of a comb.
Of, relating to or located on the chest, breast, or thorax; used to refer to a single pectoral fin in relation to fishes.
Glossary: pectoral girdle
Bony or cartilaginous structure supporting the forelimbs or anterior fins in vertebrates.
Anterior, paired fin attached to the pectoral girdle of fishes, usually just behind the opercle and corresponding to the forelimbs of higher vertebrates. Assists in controlling direction of movement and swimming speed. Frequently abbreviated to ‘P’ or ‘P1’ in scientific papers.
Of, relating to, living or occurring in the open sea rather than coastal or inland habitats.
Glossary: pelagic egg
Egg floating freely in the water column. Sometimes buoyant.
Glossary: pelagic phase
Period of time during the life cycle spent floating freely in the water column, usually as a larval constituent of plankton. Relatively common in marine fishes but also typical of amphidromous and diadromous species.
Glossary: pellet food
Commercially-produced, dried, food for fishes compressed into a hard, pelleted form. Usually comprises a combination of macro nutrients, trace elements and vitamins and may contain additional colour-enhancing, medicative or vegetable additives. Available in a range of grain sizes and brands.
Glossary: pelvic disc
Disc-shaped modification of the pelvic fins, which are often fused, used to adhere to surfaces via suction. Present in certain fishes, especially members of the family Gobiidae. Also known as sucking disc.
Glossary: pelvic fin
Either of the pair of fins, also known as pelvic fins, attached to the pelvic girdle in fishes that help control the direction of movement. Correspond to the hind legs in higher vertebrates and vary in position depending on taxon. Sometimes absent entirely.
Glossary: pelvic girdle
Bony or cartilaginous structure supporting the pelvic fins. Sometimes fused with the pectoral girdle.
Term sometimes used in reference to fishes with a colour pattern consisting of many small dots or similar markings.
Any of the appendages of a decapod that are used for walking and gathering food.
Persisting without interruption; enduring; not seasonal.
Pierce; make a hole or holes in.
Pierced with a single or number of holes, characterised by perforation.