Symbiosis is a close relationship between two different organisms that live and function together. In reef aquariums, the most important example is the partnership between corals and zooxanthellae, where both organisms benefit from working together.

SPS corals, or Small Polyp Stony corals, are reef-building corals known for their small polyps, rigid calcium carbonate skeletons, and often vibrant coloration. They are highly sought after by reef keepers for their growth forms, colors, and ability to create stunning reef displays.

Soft corals are corals that lack the large rigid calcium carbonate skeletons found in SPS and LPS corals. Known for their movement, vibrant colors, and adaptability, soft corals obtain energy through both photosynthesis and feeding while adding motion and diversity to reef aquariums.

A refugium is a separate area of a reef aquarium system designed to support beneficial organisms, nutrient export, and ecosystem stability. Commonly used to grow macroalgae and cultivate copepods, a refugium helps improve water quality while creating a more natural reef environment.

Proteins are complex molecules made from amino acids that support coral growth, tissue development, repair, and essential biological functions. They are one of the most important nutritional components corals obtain through feeding.

A protein skimmer is a filtration device that removes dissolved organic compounds and waste from aquarium water before they break down into nutrients such as nitrate and phosphate. Protein skimmers help improve water quality, increase oxygenation, and support overall reef stability.

Potassium is an essential major element found in natural seawater that supports cellular function, nutrient transport, and overall coral health. It plays an important role in coral coloration, metabolism, and biological processes throughout the reef aquarium.

Polyp extension is the visible expansion of a coral's polyps and feeding tentacles. Reef keepers often use polyp extension as an indicator of coral activity, comfort, and feeding behavior, although it should not be viewed as the sole measure of coral health.

Plankton is a general term used to describe organisms that drift through the water column and cannot actively swim against currents. In reef ecosystems, plankton serves as a major food source for corals, fish, and countless other marine organisms.

Phytoplankton are microscopic photosynthetic organisms that form the foundation of many marine food webs. In reef aquariums, phytoplankton serves as a valuable food source for filter feeders, zooplankton, and other organisms that contribute to a healthy reef ecosystem.

Phosphate is a phosphorus-based nutrient found in all reef aquariums and is essential for many biological processes, including energy transfer, cell function, and growth. While corals and other reef organisms require phosphate in small amounts, excessive levels can contribute to algae growth and reduced reef stability.

Nitrate is a nitrogen-based nutrient that forms as part of the aquarium's biological filtration process. While corals and other reef organisms can utilize nitrate in small amounts, excessive levels may contribute to algae growth and reduced water quality, making proper nutrient balance important.

Nutrient export is the process of removing excess nutrients and waste from a reef aquarium. Effective nutrient export helps maintain water quality, supports coral health, and prevents the accumulation of nitrate, phosphate, and other compounds that can negatively impact the reef ecosystem.

Nutrient balance is the relationship between the nutrients entering a reef aquarium and the nutrients being consumed, processed, or removed. Maintaining proper nutrient balance helps support coral growth, coloration, and overall reef health while preventing excessive nutrient accumulation.

Marine proteins are proteins derived from ocean-based organisms such as fish, crustaceans, plankton, and other marine life. They provide corals with highly digestible nutrition that closely resembles the food sources available on natural reefs.

Magnesium is a major element in seawater that helps maintain the balance between calcium and alkalinity while supporting numerous biological processes within a reef aquarium. Proper magnesium levels contribute to water chemistry stability, coral growth, and overall reef health.

LPS corals, or Large Polyp Stony corals, are reef-building corals known for their large fleshy polyps, visible feeding responses, and calcium carbonate skeletons. Many LPS corals readily accept supplemental feeding and are popular for their movement, coloration, and impressive growth forms.

Live rock is porous rock that contains beneficial bacteria, microorganisms, algae, and other forms of marine life. It serves as a biological filtration system, supports biodiversity, and provides habitat for countless organisms that contribute to the health and stability of a reef aquarium.

Heterotrophic feeding is the process by which corals obtain nutrients by capturing and consuming food from their environment. Unlike photosynthesis, which provides energy through symbiotic algae, heterotrophic feeding supplies corals with proteins, amino acids, fatty acids, vitamins, and other nutrients needed for growth and health.

Goniopora, often called Flowerpot Coral, is an LPS coral known for its long flowing polyps and flower-like appearance. Once considered difficult to keep, modern understanding of coral nutrition and water chemistry has made Goniopora a popular and rewarding coral for many reef keepers.