The Ultimate Guide to Saltwater Aquarium Acronyms and Terms


The Ultimate Guide To Saltwater Acronyms & Terms

I remember when I first joined this hobby, the things that overwhelmed me the most were the vast amount of acronyms, abbreviations, terms, and jargon that everyone used! I spent more time looking up the definitions than researching the topic I set out to learn!

This extensive article is designed to help you quickly find the term you are looking for so you can get back to learning more about this fantastic journey which lies ahead.

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Aa

AA – Amino Acid
A/C – Activated Carbon. Used to filter organic pollutants
AC – Electrical term for Alternating Current
ACAN – Acanthastrea Coral
ACCLIMATION – Slow change in environment when moving livestock from tank to tank
ACRYLIC – Used to create non-glass aquariums
ACRO – Abbreviation for Acropora
ACROPORA – A very popular type of coral in the SPS family
ACTINIC – Lights in the very blue part of the color spectrum
AEROBIC – Requires Oxygen
AEROBIC BACTERIA – Bacteria that need oxygen to survive
AEFW – Acro Eating Flat Worms
AGA – All Glass Aquarium ( Aquarium Manufacturer )
AIO – All-In-One Aquarium, similar to a Bio-Cube/Red Sea Max
AIPTASIA – Small nuisance anemone coral that spreads rapidly
ALK – Alkalinity
A or AMP – Electrical unit measuring the amount of current drawn by a device
AMMONIA – Toxin released by decaying matter and fish excrement
ANAEROBIC – Lack of Oxygen
ANAEROBIC BACTERIA – Bacteria that do not need oxygen to survive
AQUACULTURE – Systematic growth of aquatic livestock for commercial or personal retail and sustainability
AQUASCAPE – The art of placing Live/Dry Rock to create structure/s within the aquarium
ARAGONITE – Calcium based mineral typical used as substrate/sand
ASW – Artificial Salt Water
ATO – Automatic Top Off System. Used to replenish water lost by evaporation. See Osmolator
ATS – Algae Turf Scrubber
AWC – Automatic Water Change System

Bb

BB – Bare Bottom aquarium, no sand
BACK DRAIN – Water that flows back into sump from Return Pump Line in a power outage
BACK SIPHON – Water that continues to flow through a pipe through gravity/suction after pumping has stopped
BAFFLE – Glass panel in sump which water flows over/under
BALLAST – Type of power supply used by Fluorescent and Metal Halide lights
BALL VALVE – Plumbing valve with internal ball style gate for on/off flow control
BARBED FITTING – Barbed plumbing fitting for attaching flexible hose to pump/connector
BEAN-ANIMAL – System of Drain Pipes for silent draining aquarium
BENEFICIAL BACTERIA – Bacteria used to Convert Ammonia & Nitrites
BIO-BALLS – Plastic complex-shaped balls to provide huge surface area for bacteria to colonize
BIO-CUBE – Small All-In-One Aquarium, great for beginners
BIO-LOAD – Amount of living organisms within the aquarium system
BIOLOGICAL FILTRATION – Bacteria that consume waste in the aquarium and helps keep the ecosystem balanced
BIO-PELLETS – Bio-degradable filter polymer made from bacteria
BLASTO – Blastomussa Coral within the LPS genre
BLEACHING – When a coral loses its Zooxanthellae and turns white/pale
BRS – Bulk Reef Supply. Fantastic online store and Beginner Videos
BRYOPSIS – Miniature ‘Fern’ like nuisance algae
BUBBLE TIP or BTA – Bubble Tip Anemone
BUFFER – A solution/substance added to the water to increase Alkalinity or Ph

Cc

CAL – Calcium. Used as a building block for coral skeletons
CAP – Montipora Capricornis Coral. Grows flat like plates/shelves
CALIBRATE – To adjust a device to work, dispense or measure the correct way
CANISTER FILTER – An external filter which pumps water through it and back to the tank
CARBON – Activated Carbon is used to remove organic pollutants from the water
CBB – Copperband Butterflyfish
CBS – Coral Banded Shrimp
CFL – Compact Fluorescent. Type of light bulb, very rarely used now
CFM – Cubic Feet per Minute
CHEATO – Abbreviation for Cheatomorpha
CHEATOMORPHA – Type of macro-algae used in Refugiums
CHECK VALVE – A valve that allows water to flow only in one direction through it. See NRV
CHEMICAL FILTRATION – Used to remove toxins and specific elements from the water
CHILLER – Device used to cool aquarium water in hot climates
CHLORAMINE – Chemical disinfectant used in city water treatment
CHLORINE – A chemical used in city water treatment to kill bacteria
CMS – Cubic Meters per Second
CO2 – Carbon Dioxide
CO3 – Carbonate
CHLOROPHYL – Allows plant-based organisms to create food from light
COLONY – Large, established coral
COPEPODS – Small critters that crawl around in your aquarium and fish eat
COPPER – Used in medications to treat fish. Highly toxic to marine invertebrates
CORALLINE ALGAE – Purple, hard crust algae that grow in marine aquariums
CRUSTACEANS – Shelled invertebrates; Crabs, Shrimp Snails etc
CRS – Crystal Red Shrimp
CUC – Clean-Up-Crew. Invertebrate cleaning army for your aquarium
CYANO – Cyanobacteria. Nuisance algae
CYCLE – Aquarium Cycle. The time taken to grow biological bacteria in a new aquarium

Copper Band Butterfly
Copperband Butterfly Fish

Dd

DC – Electrical term for Direct Current
DE-CHLORINATOR – A chemical solution used to remove Chlorine from city tap water
DEIONISED WATER – Water with minimal minerals or metals in it. As close to Ph 7 as you can get
DE-IONISED – All ions removed from the water. Used to purify water
DENITRIFICATION – Anaerobic Bacteria convert Nitrates into Nitrogen gas
DETRITIVORES – Organisms that feed on Detritus
DETRITUS – Dead and decaying matter within the aquarium. Uneaten food, Poop, Dead livestock etc
DE – Double Ended. Metal Halide bulb with connection on both ends
DINO’s – Short for Dinoflagellates
DINOFLAGELLATES – An organism present in the aquarium that can have an outbreak and smother corals and Live Rock
DI – De-Ionised
DIP – Process used to sanitize coral frags of bugs and pests
DI RESIN – A resin used in water filters to help remove dissolved minerals and metals
DIY – Do It Yourself
DIATOMS – Single-cell algae that can cause outbreaks and take over the aquarium
DKH – Measure of Alkalinity
DO – Dissolved Oxygen. The amount of oxygen dissolved in the water
DOA – Dead On Arrival
DOC – Dissolved Organic Compounds
DOM – Dissolved Organic Matter
DORSAL – The fin located on the top of a fish
DOS – Dissolved Organic Solids
DOSING PUMP or DP – A pump used to pump small volumes of chemicals into the aquarium
DRAIN – The pipe from an aquarium overflow to the sump
DRY ROCK – Rock with no living organisms growing on it. Used to aquascape aquarium
DSB – Deep Sand Bed
DT – Display Tank. Your main aquarium
DURSO – Type of drain pipe system used to reduce ‘Slurping Noise’

Ee

EGG CRATE – Plastic light diffuser made of squares. Makes great frag racks
EHEIM – Excellent manufacturer of aquarium equipment
ELBOW – A plumbing fitting used to change the angle of a pipe. 90° & 45° are most common
ENCROACHING – A coral expanding into a neighbors territory
EMERALD CRAB – Green crab also know as a Mithrax Crab. Good at removing Bubble Algae
ENGINEER GOBY – Type of fish that loves to make a burrow in the sand bed
EPOXY – Reef Safe Epoxy used to cement rocks together and fix coral frags to the rock
EUPHYLLIA – Type of coral. Good beginner coral
EUROBRACE – Glass strips that go around the top and bottom of the aquarium to add strength
EVAPORATION – Freshwater lost to the atmosphere because of the warm water temperature
EXTERNAL FILTER – A filter housed outside of the aquarium.

Fe

FAQ – Frequently Asked Questions
FALLOW – Leaving the aquarium running without fish to eradicate Ich
FEMALE FITTING – Plumbing fitting where the pipe fits into the inside of the fitting
FILTER – A device, organism or product used to clean water
FILTER FEEDER – An animal/organism that feeds on the microscopic foods floating within the water
FILTER MEDIA – Products manufactured to catch detritus or provide a surface area for bacteria to colonize on or within
FILTER SOCK – A felt sock used to mechanically catch solids from the water
FINROT – Bacterial disease that causes the fins on fish to start receeding
FLAKES – Fish food in the form of very, very thin wafer-like flakes
FLATWORMS – Nuisance pest that compete for microscopic food with Pods and Filter Feeders
FLOSS – Synthetic fluff used to mechanically capture floating solids in the water for removal
FLOW RATE – The amount of water moved in a given time. See GPH
FLUIDIZED BED – Type of filter that keeps the filter media moving to provide maximum surface area to beneficial bacteria
FO – Fish Only
FOLR – Fish Only Live Rock
FOWLR – Fish Only with Live Rock
FRAG – Abbreviated term for Fragmentation and a small piece of coral
FRAGMENTATION – Cutting off a piece of coral to regrow into a separate colony
FRAG PLUG – Small ceramic disks/plates used to superglue coral frags to
FRAG RACK – A device used to hold coral frags
FRAG TANK – Tank/Aquarium dedicated to growing Frags
FROZEN FOOD – Store bought or a DIY mix of seafood, fish food and additives blended together and frozen
FTS – Full Tank Shot. Photograph of your whole aquarium
FUGE – Abbreviated term for Refugium
FW – Fresh Water

CPR HOB Refugium
Hang On Back ‘Fuge’

Gg

GAC – Granular Activated Carbon
GAL – Abbreviation for Gallon
GATE VALVE – Type of valve used to fine-tune water flow rate through a pipe
GBTA – Green Bubble Tip Anemone
GFCI – Ground Fault Circuit Interrupt. Type of electrical socket installed to keep you from being electrocuted
GFO – Granular Ferric Oxide. Helps remove phosphate
GHA – Green Hair Algae
GILLS – Part of a fish used to remove oxygen from the water
GPD – Gallons Per Day
GPH – Gallons Per Hour
GPM – Gallons Per Minute
GRAVITY DRAIN – Water flows into the drain then falls under gravity out of the vessel/container/aquarium/overflow
GRAVITY FED – Water drains down to feed it using gravity
GSP – Green Star Polyps. Type of fast-growing coral
GUNK – Slang for brown sludge or any icky substance
GYRE – Crossflow wave maker from Maxspect

Hh

HAIR ALGAE – Nuisance algae that can overrun an aquarium
HEATER – Device used to keep water warmed to correct temperature
HEAVY METALS – Metals dissolved in water. Toxic to fish, invertebrates, and corals
HERBIE – A type of drain system used to help aquarium drain silently into a sump
HERBIVORE – An animal that feeds entirely on plant-based matter
HERMIT CRAB – A species of Crab that use snail shells as their home/protection
HO – High Output. Usually used with lighting specifications
HOB – Hang-On-Back
HOT – Hang-On-Tank
HT – Abbreviation for Hospital Tank
HOSPITAL TANK – Aquarium dedicated to rehabilitation of sick fish
HQI – Hydrargyrum Quartz Iodide. Type of Metal Halide bulb used in lighting
HYDROMETER – Plastic device used to poorly measure salt content within saltwater
HYPOXIA – When an animal is unable to consume enough oxygen from the water. Caused by pollution, algae outbreak, poor water quality control

Ii

ICH – Easily spread fish disease
ICK – See Ich
IMPELLER – Rotating part of a Pump or Powerhead that moves the water
INVERT – Abbreviation for Invertebrate
INVERTEBRATE – Animal with no backbone. Snail, Shrimp, Crab etc
IODINE – Trace element used by corals for growth and color
IO – Instant Ocean. Popular brand of aquarium salt mix

Jj

JBJ – Aquarium equipment manufacturer
JOE’s JUICE – Solution used to kill Aiptasia
JOURNAL – Used to record parameters when cycling or dosing
JUWEL – European aquarium manufacturer
JULIAN SPRUNG – Well known Aquarist. Brand of aquarium products

Joe's Juice Aiptasia Eliminator
Joe’s Juice Aiptasia Eliminator

Kk

KALK – Abbreviated term for Kalkwasser
KALKWASSER – A powder used to make a solution to supplement Calcium
KELVIN – Lighting term used to describe the color of the light/bulb
KRILL – Small crustaceans used to feed fish. Frozen or freeze-dried
KWH – Electrical term for Kilowatt Hour

Ll

LARVE – Beginning stage of life after hatching for many fish and invertebrates
LED – Abbreviation for Light Emitting Diode. Type of light system used on marine aquariums
LIVE FOOD – Living food grown and fed to the aquarium. Plankton, Copepods, Rotifers etc
LIVE ROCK – Rock from an established marine environment and covered with marine life. Used to aquascape aquarium
LIVE SAND – Sand containing living, beneficial bacteria. Used in marine aquariums
LFS – Local Fish Store
LOC-LINE – Flexible sectioned pipe used with Return Nozzles
LPS – Large Polyp Stony. Type of coral
LR – Abbreviation for Live Rock

Mm

MACROALGAE – Aquatic plants mainly grown in a Refugium to help nutrient export
MACNA – Marine Aquaria Conference of North America. The mecca for ‘Reef Nerds’ like me!
MAG – Abbreviation for Magnesium
MAGNESIUM – An element rapidly used in coral growth.
MAG FLOAT – A popular brand of Magnetic Algae Cleaner
MAGNETIC ALGAE CLEANER – A cleaning product in 2 halves. One goes on the inside of the glass, the other on the outside of the glass. Cleans algae off glass
MALE FITTING – Plumbing fitting that fits into the inside of the pipe
MANIFOLD – Series of plumbing fittings used to supply water to multiple pieces of equipment
MARINE DEPOT – Great Supplier to the Saltwater Aquarium hobbyist
MARINE FAUNA – Microscopic organisms that keep the aquarium clean and become a food source
MECHANICAL FILTRATION – Floss, Sponges or Filter Socks used to physically remove solids from the water
MEDIA -A generic term used to describe the parts of the filter used to keep the water clean or grow bacteria on
MEDIUM – Another term used to describe Media
METAL HALIDE – Type of light bulb/system
MH – Abbreviation for Metal Halide
MILLI – Abbreviation for Millipora
MILLIPORA – Type of SPS coral
MICROALGAE – Microscopic aquatic plants fed on by filter feeders. Most nuisance algae are types of Microalgae
MICROFAUNA – See Marine Fauna
MONTI – Abbreviation for Montipora
MONTIPORA – A genre of coral within the SPS range of corals
MULTIPLE TANK SYNDROME – Aquarists with multiple aquariums
MUSHROOMS – A great beginner soft coral

Nn

NANO-REEF – A reef aquarium under 30 gallons
NEM – Abbreviated term for Anemone
NECROSIS – A bacterial infection on SPS corals leading to skin peeling and death. See RTN & STN
NITRATES – Nitrites are converted into nitrates by bacteria. Part of Nitrogen Cycle
NITRITES – Ammonia is converted into nitrites by bacteria. Part of Nitrogen Cycle
NITRIFICATION – The process of bacteria converting Ammonia to Nitrites, then to Nitrates
NITRIFYING BACTERIA – The bacteria colonized in your aquarium that take care of the Nitrogen Cycle
NITROBACTER – Type of bacteria that turn Nitrites into Nitrates
NITROGEN CYCLE – The natural process of turning Ammonia into Nitrates
NITROSOMONAS – Type of bacteria that turn Ammonia into Nitrites
NPS – Non-Photosynthetic Coral. Coral that only gets energy from food and not light
NPT FITTING – Threaded pipe fitting
NUTRIENT EXPORT – The removal of excess nutrients from the aquarium
NTS – Abbreviation of New Tank Syndrome
NEW TANK SYNDROME – When fish are living in water with high levels of Ammonia. Fish added too soon before aquarium has cycled fully
NRV – Non-Return Valve. A plumbing valve that only allows water to flow in one direction. See Check Valve
NSL – Natural Sunlight
NSW – Natural Sea Water
NUDI – Abbreviation for Nudibranch
NUDIBRANCH – Sea Slug like creature. Very difficult to prevent them from starving in an aquarium

Nudibranch
Nudibranch

Oo

ORP – Oxidation Reduction Potential. A measure of the waters ability to clean itself
OSMOLATOR – Device that automatically replaces water lost through evaporation. See Auto Top-Off
OSMOSIS – Liquid passes through a special membrane to filter it. Used to filter city water
O2 – Oxygen
O3 – Ozone. Very reactive form of Oxygen used in filtration
OCTCR – Oh Crap That’s The Carpet Ruined! Just Checking you are still alert!!!!!
OVERFLOW – Small box that sits in the top of the aquarium that drains water into the sump
OZONIZER – A device that uses electricity to create Ozone

Pp

PALY – Abbreviation for Palythoa. Type of coral
PALYTOXIN POISONING – Toxin associated with some Palythoa
PAR – The amount of light that penetrates the water column
PARAMETER – A desired value of a specific item to monitor within the aquarium eg: Temperature, Salinity, Ph etc
PARASITE – An organism that lives on another living animal
PC – Power Compact. Type of lighting system
PERISTALTIC PUMP – Type of pump that squeezes fluid through a hose. Used for dosing supplements
PH – The measure of how acid or alkali water is
PHOSPHATE – A trace element that impedes coral growth and encourages algae growth
PHOTOPERIOD – The time your aquarium lights are on
PHOTOSYNTHESIS – The process used by plant-based organisms to create energy from light
PICO-REEF – A reef aquarium under 5 gallons
PLANKTON – Diverse range of microscopic organisms that feed the world’s oceans
PLUG – See Frag Plug
POLYP – Single head of coral
POWER HEAD – Water pump that sits in the water to move water in the aquarium or from a vessel to another location
PPM – Parts Per Million
PRIME – Chemical solution used to make Chlorine in city tap water safe
PROTEIN SKIMMER – A major filtration device used in saltwater aquariums. Uses bubbles to remove food and waste from the water
PROPAGATION – Dissecting of corals and creating coral frags for growth or resale
PVC – Type of plastic pipe used to plumb aquariums and life support system

Qq

QT – Abbreviation for Quarantine
Quarantine – The removal of a sick animal to be individually medicated or prevent the spread of disease
Quarantine Tank – Aquarium dedicated to the treatment of a sick fish. See Hospital Tank

Rr

RADION – Popular LED Light unit from EcoTech Marine
RBTA – Rose Bubble Tip Anemone
RC – Reef Crystals. Popular salt mix
REACTOR – Stand-alone vessel mounted by/in the sump to house additional filter media
REDOX – See ORP
REEFER – A person addicted to this fantastic hobby!
REEF READY – An aquarium with pre-installed overflow, drain and return plumbing from the manufacturer
REFUGIUM – An area dedicated to the growth of Macroalgae and Marine Fauna
REFLECTOR – Mirrored shroud that sits on top of your lights to reflect all the energy into the aquarium
REFRACTOMETER – Device used to accurately measure the dissolved salt content in your water
RETURN NOZZLE – Shaped nozzle on the end of the return pipe to help direct flow into the aquarium
RETURN PIPE – The pipe connecting the Return Pump to the aquarium
RETURN PUMP – Pump that moves water from the sump back into the aquarium
RICS – Abbreviation for Ricordia
RICORDIA – Type of coral
RIMLESS – Aquarium with no brace or plastic molding around the top edges.
RO – Abbreviation for Reverse Osmosis
REVERSE OSMOSIS – Similar to Osmosis but passes water the opposite way through the membrane
RO/DI – Water filtration system every Reefer should own!
ROLLER MAT – Mechanical device that automatically removes solid particles from the water and keeps the filter renewed with fresh mat
RTN – Rapid Tissue Necrosis. See Necrosis

Rose Bubble Tip
Rose Bubble Tip Anemone

Ss

SALINITY – The amount of dissolved salt contained in a body of water
SCHEDULE 40 – White PVC pipe and fittings used in aquarium plumbing
SCHEDULE 80 – Gray, heavier duty PVC pipe and fittings used in aquarium plumbing
SE – Single Ended. Metal Halide bulb with connection on one end only
SHROOM – Abbreviation for Mushroom Corals
SILICONE SEALANT – Chemical agent used to bond glass panes together to create the aquarium
SIPHON – When water continues to flow through a pipe after initial suction has ended.
SIPHON BREAK – A hole in the pipe to break the siphon on a pipe
SKIMMER – Abbreviation for Protein Skimmer
SLIP FITTING – A smooth plumbing fitting designed to be glued to a pipe
SOFTIES – Abbreviation for Soft Corals
SOFT CORAL – A genre of coral with no skeleton
SOLENOID VALVE – A fluid valve that can be electrically controlled
SG – Abbreviation for Specific Gravity
SPECIFIC GRAVITY – The ratio of salt to water
SPONGE – a filter feeding coral
SPONGE FILTER – A sponge block used to trap particles and/or home bacteria in your biological filter
SPS – Abbreviation for Small Polyped Stony. Type of Coral
STAND – The furniture your aquarium sits on
STARFIRE – A type of ultra clear glass used by aquarium manufacturers
STICKS – A common nickname for SPS corals due to their appearance
STN – Slow Tissue Necrosis. See Necrosis
STONY – Abbreviation for SPS
SUMP – A remotely installed vessel/ tank to house life support and filtration equipment
SUPPLEMENTS – Chemicals added to the water to increase specific parameters or meet the demand of coral consumption
SW – Salt Water
SWEEPER – A tentacle or polyp extended by a coral to sting encroaching neighbors
SYMBIOTIC – The living relationship between organisms in a closed environment like an aquarium

Tt

T5 – Type of popular light bulb used to grow coral
TDS – Total Dissolved Solids. A measure of tap water cleanliness
TEE – Plumbing fitting in the shape of a ‘T’ used to connect 3 pipes
TEST KIT – Chemical test used to accurately measure a specific element
TITRATION – Slow addition on one chemical to another until a reaction takes place. The basis of most aquarium test kits
TORCH – Type of coral
TRACE ELEMENTS – Small elements that make up part of the water chemistry
TRACHYPHYLLIA – Type of coral
TRICKLE FILTER – Water is allowed to slowly tickle through filter media to provide large contact time with the biological filter bacteria
TURNOVER – The amount of flow rate through the aquarium system

Uu

UNLS – Ultra Low Nutrient System
UV – Ultra Violet
ULTRA-VIOLET STERILIZER – A device which passes water over a UV bulb to sterilize bacteria

Torch Coral Garden
Torch Coral Garden

Vv

VELVET – Marine Velvet is a common fish disease
VENTURI – A device used to accelerate water flow
VERTEBRATE – An animal with a spine and skeleton
VHO – Very High Output. Type of aquarium lighting system
VOLTS – Electrical unit measuring the amount of voltage used by a device

Ww

WATTS – Electrical unit measuring the amount of power used by a device
WATER CHANGE – Removal of water from the aquarium and replaced with new salt mix
W/C – Abbreviation for Water Change
WYSIWYG – What You See Is What You Get
WELLSO – Abbreviation for Wellsophyllia
WELLSOPHYLLIA – Type of coral

Xx


Yy

YWG – Yellow Watchman Goby

Zz

ZOA – Abbreviation for Zoanthid
ZOOS – Abbreviation for Zoanthid
ZOANTHID – Type of coral
ZOOPLANKTON – Plankton consisting of microscopic animals
ZOOXANTHELLAE – A photosynthetic algae that live in coral and provide the coral with its energy

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Richard

Hi, I'm Richard and I have been an avid aquarist for over 30 years with a passion for Saltwater Aquariums. I love to pass on my knowledge to help others get the same amount a pleasure out of this hobby as I do. View my About Me page to find out more about me & my mixed reef aquarium.

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