Frequently Asked Questions
The most-asked questions about reef aquarium species.
What exactly is a reef aquarium?
A reef aquarium is a saltwater tank that recreates a natural coral-reef ecosystem, housing living corals, reef fish, and invertebrates in a tightly balanced system. It goes beyond a simple saltwater setup by demanding precise water chemistry and attention to the symbiotic relationships among its inhabitants.
What are the main categories of species kept in a reef tank?
The three broad groups are stony and soft corals, reef-safe fish (chromis, tangs, anthias, etc.), and invertebrates such as cleaner shrimp, hermit crabs, and nudibranchs. Every category depends on stable salinity, alkalinity, calcium, and magnesium, though their individual tolerances vary widely.
Which species are considered the most beginner-friendly?
Soft corals like leather corals, bird's-eye corals, and zoanthids are widely recommended as first corals because they absorb minor parameter swings better than stony species. On the fish side, damselfish and a few hardy gobies are often suggested as low-stress, forgiving options for new reef keepers.
What water parameters are critical for a healthy reef system?
Most reef species thrive at a salinity near 1.025, alkalinity of 8–12 dKH, calcium around 400–450 ppm, and magnesium close to 1,300 ppm. Temperature is typically held between 76 and 80 °F (24–27 °C), and nitrate should stay under 10 ppm to avoid coral stress.
What is the most iconic or 'flagship' species in the reef hobby?
The clownfish (Amphiprioninae) is arguably the most recognizable reef species, boosted by the Nemo franchise and commonly kept as a first reef fish. Among corals, the Acropora genus is often called the jewel of the reef for its dramatic branching forms and vivid coloration.
How long do typical reef aquarium species live?
Many reef fish such as tangs and wrasses can reach 10–20 years in captivity, while stony corals like Acropora may continue growing for decades under stable conditions. Some invertebrates, including certain nudibranchs, live only a few months, making their presence a brief but memorable highlight.
Which species are considered the most challenging to keep?
LPS corals like Euphyllia and delicate zoanthid hybrids are popular yet sensitive to shifts in light, flow, and water quality. On the fish side, mandarinfish and some specialized wrasses are notoriously finicky about diet and stability, often labeled expert-only.
What's the difference between a reef tank and a FOWLR setup?
A FOWLR (Fish Only With Live Rock) tank houses reef-safe fish and live rock but omits living corals, easing demands on lighting and trace-element stability. A full reef tank adds stony and soft corals, which raises the bar for photoperiod, flow, and overall water-chemistry precision.
Where should a newcomer start building a reef collection?
Most experienced keepers advise beginning with a small, well-cycled tank (40–60 gallons), a quality protein skimmer, and a handful of hardy soft corals before attempting stony species. Introducing one or two fish at a time and monitoring parameters daily for the first two months helps prevent costly crashes.
Are reef aquarium species wild-caught or captive-bred?
The hobby historically relied heavily on wild-caught specimens from the Indo-Pacific, but captive breeding of clownfish, certain chromis, and select corals has grown substantially. Ethical sourcing and supporting captive-bred programs are increasingly central topics in the reef community.