Glossary

Aquascaping terms, in plain English

Every bit of jargon you'll meet in the hobby, defined simply. Where a term has a full guide, the definition links to it.

Ammonia (NH₃): The first and most toxic nitrogen waste from fish and rotting food. Should read zero in a cycled tank.
Aquascaping: The craft of arranging plants, stone, wood and substrate into a designed underwater landscape, not just a stocked tank.
Aquasoil: An active, nutrient-rich soil substrate that feeds plant roots and gently softens and acidifies the water for the first year or so.
Biofilm: The thin, natural layer of microbes and bacteria that coats surfaces in a tank. Food for shrimp and fry, and a sign of a maturing tank.
Bioload: The total waste your livestock produces, which the biofilter and plants must process. Overstocking raises it past what the tank can handle.
Biotope: A layout that faithfully recreates one real habitat, using only the species, hardscape and water that place would actually have.
Blackwater: Soft, acidic, tea-stained water created by tannins from wood and leaf litter, mimicking Amazon and Southeast Asian streams.
Caridina: A genus of shrimp, including crystal and bee shrimp, that wants soft, acidic, low-mineral water. Fussier than neocaridina.
Carpet plant: A low, spreading plant grown to cover the foreground like a lawn, such as Monte Carlo or dwarf hairgrass.
CO₂ injection: Adding carbon dioxide gas to the water so plants can photosynthesise faster. The biggest lever in a high-tech planted tank.
Cycling: Growing the bacteria that turn toxic ammonia into nitrite and then into far less toxic nitrate, before adding livestock.
Deficiency: A plant symptom, such as yellowing or pinholes, caused by a shortage of a specific nutrient like nitrogen, iron or potassium.
Dosing: Adding fertiliser to the water on a schedule to supply the nutrients plants need beyond what the substrate and fish provide.
Drop checker: A small glass indicator with a coloured solution that shows, by turning lime green, whether CO₂ is at a good level.
Dry start: Growing carpet plants emersed (out of water) in a humid, shallow-filled tank before flooding it, to establish them faster.
Emersed: Grown with leaves above the waterline, in humid air rather than submerged. Many aquarium plants are farmed this way.
Epiphyte: A plant like anubias or java fern that attaches to wood or rock rather than rooting in substrate. Its rhizome must stay uncovered.
Estimative Index (EI): A dosing method that supplies generous, non-limiting nutrients and resets with a large weekly water change.
GH (general hardness): The dissolved calcium and magnesium in the water, the minerals plants and shrimp need. Measured in dGH.
Hardscape: The non-living structure of a scape: stone, wood and the way they're arranged.
Ich (white spot): A common parasite that appears as salt-like white spots on fish, usually after a chill or stress.
Iwagumi: A minimalist style using only stone (no wood) over a single carpeting plant, where all the drama is in rock placement.
KH (carbonate hardness): The carbonate buffer that keeps pH stable. Low KH means an unstable pH that can crash overnight.
Melt: When a plant, often a crypt, sheds its leaves after being moved or after a parameter change, then regrows from the roots.
Molt: How shrimp grow, shedding the old shell for a new one. Failed molts point to a general-hardness or mineral problem.
Neocaridina: A genus of hardy shrimp, including cherry shrimp, that tolerates a wide range of harder, neutral water. The beginner's shrimp.
Nitrate (NO₃⁻): The least toxic end of the nitrogen cycle, removed by water changes and taken up by plants. A stress and algae driver when high.
Nitrite (NO₂⁻): The toxic middle stage of the nitrogen cycle. Should read zero in a cycled tank.
Nitrogen cycle: The bacterial process that converts ammonia to nitrite to nitrate, making a tank safe for fish.
PAR: Photosynthetically active radiation, a measure of the usable light reaching your plants. It drives how demanding a plant you can grow.
pH: How acidic or alkaline the water is. Stability matters more than hitting an exact number.
Photoperiod: How long the lights are on each day. Too long or too bright for the plant mass invites algae.
Remineraliser: A product that adds calcium, magnesium and other minerals back into RO water to a target GH, for plants and shrimp.
Rhizome: The horizontal stem of epiphytes like anubias and ferns, from which leaves and roots grow. It must not be buried.
RO / RODI water: Reverse-osmosis water stripped of minerals, used as a blank slate to build soft or precisely controlled water.
Root tabs: Nutrient capsules pushed into inert substrate to feed heavy root feeders like swords and crypts.
Rule of thirds: A composition guide: place the focal point on a line a third of the way across, not centred, for a more natural layout.
Silent cycle: Cycling a heavily planted tank where fast plants absorb ammonia directly, so the toxic spike barely shows.
Stem plant: A fast-growing plant grown from cut stems, replanted and trimmed to shape. The backbone of Dutch and background planting.
Substrate: The material on the tank floor, from inert sand and gravel to active aquasoil, that anchors plants and shapes water chemistry.
Tannins: Compounds leached by wood and leaves that tint water amber, soften it slightly and lower pH. Harmless and often desirable.
TDS: Total dissolved solids, a rough ppm measure of everything dissolved in the water. Useful for tracking shrimp-tank stability.
Walstad method: A low-tech approach using soil and heavy planting to balance a tank with no CO₂ and minimal filtration.
Water column: The open water between substrate and surface, and where in it a fish or plant lives or feeds (top, middle, bottom).