Display Aquarium (L2S3A) reef · 3900 L

Who lives here

Anemone hermit crab Dardanus pedunculatus

arthropod · Hermit crabup to 12 cmswims: bottomsemi-aggressivemarine waterIUCN NE · Not Evaluated

A hermit crab that plants living sea anemones on its borrowed shell for defence; a scavenger that roams the sandy sea floor.

📍 Native range: Indo-West Pacific — Red Sea & East Africa to Japan, Hawaii & Australia

Diet: mainly other invertebrates, other fish, molluscs

Watch for: moving / crawling · feeding · moulting

🔬 Classification

Animalia›Arthropoda›Malacostraca›Dardanus›D. pedunculatus

Kingdom	Animalia
Phylum	Arthropoda
Class	Malacostraca
Genus	Dardanus
Species	D. pedunculatus

SeaLifeBase ↗ WoRMS ↗ IUCN Red List ↗

Bald glassy سمكة زجاجية Ambassis gymnocephalus

fish · Glassfishup to 9 cmswims: midpeacefulbrackish waterIUCN LC · Least Concern

A translucent “glassfish” of shallow estuaries; a nocturnal feeder on plankton and small prey.

📍 Native range: Indo-West Pacific — East Africa to the Philippines and northern Australia

Diet (see references): Wild: zooplankton-dominant + small crustaceans.

Watch for: swimming (active) · feeding · shoaling / schooling · chasing

🔬 Classification

Animalia›Chordata›Actinopterygii›Perciformes›Ambassidae›Ambassis›A. gymnocephalus

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Perciformes
Family	Ambassidae
Genus	Ambassis
Species	A. gymnocephalus

FishBase ↗ IUCN Red List ↗

Black-spotted butterflyfish فراشة منقّطة Chaetodon nigropunctatus

fish · Butterflyfishup to 14 cmswims: midpeacefulmarine waterIUCN LC · Least Concern

A butterflyfish that feeds on coral polyps and small invertebrates, usually seen in pairs.

📍 Native range: Arabian Gulf, Gulf of Oman & Arabian Peninsula to East Africa

Diet (see references): Wild: mainly live coral polyps + benthic inverts (corallivore-leaning).

Watch for: swimming (active) · feeding · shoaling / schooling · chasing

🔬 Classification

Animalia›Chordata›Actinopterygii›Perciformes›Chaetodontidae›Chaetodon›C. nigropunctatus

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Perciformes
Family	Chaetodontidae
Genus	Chaetodon
Species	C. nigropunctatus

FishBase ↗ IUCN Red List ↗

Blue-barred (yellowscale) parrotfish Scarus ghobban

fish · Parrotfishup to 60 cmswims: midsemi-aggressivereef waterIUCN LC · Least Concern

The commonest large parrotfish of the Arabian Gulf; it scrapes algae from rock with a fused beak and grinds the swallowed coral rock into fine sand.

📍 Native range: Indo-Pacific — Red Sea, Arabian Gulf & East Africa east to Japan and Australia, and on to the eastern Pacific

Diet: mainly algae & plants, plankton

Watch for: swimming (active) · feeding · shoaling / schooling · chasing

🔬 Classification

Animalia›Chordata›Actinopterygii›Perciformes›Scaridae›Scarus›S. ghobban

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Perciformes
Family	Scaridae
Genus	Scarus
Species	S. ghobban

FishBase ↗ IUCN Red List ↗

Bluetail Trunkfish سمكة صندوقية زرقاء الذيل Ostracion cyanurus

fish · Boxfishup to 15 cmswims: midpeacefulmarine waterIUCN NE · Not Evaluated

A small boxfish armoured in fused bony plates; males have a vivid blue tail.

📍 Native range: Western Indian Ocean — Red Sea to the Arabian Gulf

Diet (see references): Genus-level: benthic inverts (tunicates/worms/molluscs/crustaceans) + some algae; app’s algae share likely high.

Watch for: swimming (active) · feeding · shoaling / schooling · chasing

🔬 Classification

Animalia›Chordata›Actinopterygii›Tetraodontiformes›Ostraciidae›Ostracion›O. cyanurus

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Tetraodontiformes
Family	Ostraciidae
Genus	Ostracion
Species	O. cyanurus

FishBase ↗ IUCN Red List ↗

Horseshoe butterflyfish فراشة حدوة الحصان Chaetodon pictus

fish · Butterflyfishup to 10 cmswims: midpeacefulmarine waterIUCN LC · Least Concern

A butterflyfish named for the horseshoe mark where its body band meets the dorsal fin.

📍 Native range: Western Indian Ocean — Red Sea, Oman & Gulf of Aden

Diet (see references): Genus-level: coral polyps / zooplankton / benthic inverts.

Watch for: swimming (active) · feeding · shoaling / schooling · chasing

🔬 Classification

Animalia›Chordata›Actinopterygii›Perciformes›Chaetodontidae›Chaetodon›C. pictus

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Perciformes
Family	Chaetodontidae
Genus	Chaetodon
Species	C. pictus

FishBase ↗ IUCN Red List ↗

Sergeant Major سمكة الرقيب Abudefduf saxatilis

fish · Damselup to 15 cmswims: midaggressivemarine waterIUCN LC · Least Concern

A hardy damselfish with five black bars; males guard purple egg patches on rock.

📍 Native range: Tropical Atlantic Ocean (the look-alike Indo-Pacific sergeant is Abudefduf vaigiensis)

Diet (see references): Wild: copepods & amphipods dominant, then algae, fish eggs.

Watch for: swimming (active) · feeding · shoaling / schooling · chasing

🔬 Classification

Animalia›Chordata›Actinopterygii›Perciformes›Pomacentridae›Abudefduf›A. saxatilis

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Perciformes
Family	Pomacentridae
Genus	Abudefduf
Species	A. saxatilis

FishBase ↗ IUCN Red List ↗

Silver moony القمر الفضي Monodactylus argenteus

fish · Moonyup to 15 cmswims: midsemi-aggressivebrackish waterIUCN LC · Least Concern

A silvery, disc-shaped schooling fish of mangrove estuaries and bays; tolerates brackish water.

📍 Native range: Indo-West Pacific — Red Sea & East Africa to Samoa

Diet (see references): Wild/estuarine: algae + detritus with copepods/crustaceans.

Watch for: swimming (active) · feeding · shoaling / schooling · chasing

🔬 Classification

Animalia›Chordata›Actinopterygii›Perciformes›Monodactylidae›Monodactylus›M. argenteus

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Perciformes
Family	Monodactylidae
Genus	Monodactylus
Species	M. argenteus

FishBase ↗ IUCN Red List ↗

White-spotted rabbitfish الصافي Siganus canaliculatus

fish · Rabbitfishup to 20 cmswims: midpeacefulmarine waterIUCN LC · Least Concern

A herbivorous rabbitfish of seagrass and algal flats; the fin spines are venomous.

📍 Native range: Indo-West Pacific — Arabian Gulf & Gulf of Oman to the western Pacific

Diet (see references): Wild: herbivore — algae 30–78%, seagrass, minor plankton/detritus.

Watch for: swimming (active) · feeding · shoaling / schooling · chasing

🔬 Classification

Animalia›Chordata›Actinopterygii›Perciformes›Siganidae›Siganus›S. canaliculatus

Kingdom	Animalia
Phylum	Chordata
Class	Actinopterygii
Order	Perciformes
Family	Siganidae
Genus	Siganus
Species	S. canaliculatus

FishBase ↗ IUCN Red List ↗

How big are they?

A scuba diver’s body holds a lot of fish! The picture shows how many bald glassy it takes to fill a diver’s volume — about 5,400. Here is roughly how many of each animal would match one diver:

Approximate whole-body volume ratios (a diver ≈ 70 litres).

How they get along

This community includes assertive species; feeding is spread across the tank so shy fish still get their share.

Reading their behaviour

Keepers here do not just check the water — they watch the animals, to a written list, every day. That list is called an ethogram.

What to watch for in this exhibit

This is the real watch-list for the animals in front of you, taken from their own ethograms. How many can you catch?

How we plan their diet

Every animal here is fed a diet built around what it eats in the wild. We research each species’ natural diet from published science, sort foods into the same groups nature uses — fish, crustaceans, molluscs, other invertebrates, plankton and algae or plants — and blend products so each meal delivers the right balance of protein, fat and energy for that species. The daily amount is worked out from the combined weight of the animals in the tank and how much of their body weight each one needs, then divided into several meals through the day. Fast and slow eaters are handled differently: bolder fish are fed first, shy or slow feeders are target-fed by hand or feeding stick, and floating and sinking foods are offered together so surface, mid-water and bottom feeders all get their share. Keepers check each animal’s body condition every week and fine-tune the plan.

What we measure — and why

Life support & lighting

• Recirculation pumpMoves water continuously around the whole system, keeping warmth, oxygen and food evenly spread and driving every treatment stage.↔ The recirculation pump does the opposite job: it moves the same water round a closed loop several times an hour. What counts is turnover — how often every litre revisits the treatment — not how far it travels.
• UV steriliserWater passes a high-intensity ultraviolet lamp that neutralises free-floating bacteria, parasites and algae spores — disease control without chemicals.↔ On the exhibit loop the same water crosses the lamp again and again, several times a day. That repetition is what breaks a parasite’s life cycle between the fish already living here — something the intake lamp can never do, because it only ever sees each litre once.
• Temperature regulationHeaters and chillers hold the water in a narrow tropical range; a steady temperature keeps fish and corals unstressed.↔ On the exhibit the job is the opposite — not changing the temperature but refusing to let it change, minute by minute, against room heat, the lamps and the pumps.
• Flow sensor & flow metersContinuously measure how fast water moves through each loop, confirming every animal gets fresh, oxygen-rich water and flagging a blockage early.
• Protein skimmerInjects a column of fine bubbles that grab dissolved organic waste before it breaks down, exporting it as foam and keeping the water clear.↔ On the exhibit the skimmer deals with what the animals themselves produce — uneaten food, mucus and faeces — pulled out continuously, before bacteria can turn it into ammonia.
• Level sensorWatches the water height and tops up automatically for evaporation, holding salinity steady and protecting the pumps.
• Monitoring & automation systemA central controller logs temperature, pH, salinity and flow around the clock, runs the equipment on schedule and alerts staff to anything out of range.
• BiofilterA bed of beneficial bacteria turns toxic ammonia from animal waste into harmless nitrate — the biological heart of the system.
• Mechanical sand filterWater is driven through a fine sand bed that traps suspended particles, polishing it before it returns to the exhibit.↔ Inside the exhibit the water is already clean, so the sand bed is polishing rather than cleaning — catching the fine particles the animals stir up, on every pass.

Lighting: Programmable LED lighting reproduces a natural marine day across a full 380–700 nm spectrum. It blends an 18,000 K and a 14,000 K white channel — a bright, slightly blue-shifted daylight — with a wide-blue channel and a pure-blue (actinic) channel that push the blue wavelengths reef corals rely on for photosynthesis and that make many corals fluoresce. True-ultraviolet (380 nm) diodes add the near-UV edge of real sunlight. The lights follow the same gentle dawn-to-dusk ramp and low night setting every day: this fixed, imposed circadian rhythm keeps the animals’ internal body clocks in step, so they feed, rest and behave naturally and with far less stress.

Four channels, one daylight. Each lamp adds a different part of the spectrum; together they build a bright, blue-shifted reef daylight:

White 18000 K

White 14000 K

Wide blue

Blue (actinic)

Add them together and this is the combined spectrum the corals and fish actually receive:

Watch the four channels stack up, one at a time, into the single spectrum the exhibit runs on.

What the light is doing

• Blue light reaches deepestSeawater soaks up red, orange and yellow light within the first few metres. Blue travels much further down, so the deeper you go the bluer the world looks — and reef animals evolved under that blue-dominated light.
• Corals farm algae called zooxanthellaeReef corals get most of their energy from microscopic algae, the zooxanthellae, living inside their own tissue. The algae photosynthesise and feed the coral, which is why a coral needs light as much as it needs food.
• Why reef lights are so blueBecause the corals’ algae live on the blue light that reaches reef depth. A blue-rich lamp gives them the light they are built for, and it makes the exhibit look like the real reef rather than a brightly lit fish bowl.
• Blue and red drive photosynthesisThe pigments in the algae absorb blue and red wavelengths most strongly and use green least — that is why healthy corals and plants look green, and why our lamps deliberately carry both a strong blue and a red shoulder.
• Corals glow — that is fluorescenceMany corals contain proteins that catch blue and near-ultraviolet light and re-emit it as green, orange or red. That re-emission is called fluorescence: the coral is not reflecting the colour, it is producing it.
• What 14,000–18,000 K meansColour temperature in kelvin (K) describes the tint of white light, not its warmth. Candlelight is around 2,000 K and a warm orange sunset low; 14,000–18,000 K is a bright, slightly blue tropical midday sun seen from underwater — the look this system is set to.
• A touch of near-ultravioletDiodes at about 380 nm add the near-UV edge that real sunlight carries. It is the wavelength that triggers the strongest coral fluorescence, so it deepens their colour; the levels used are those found on a natural reef.
• A fixed dawn-to-dusk dayThe lamps ramp up gently each morning, hold a bright midday, fade at dusk and drop to a dim night setting — the same times every day. That steady circadian rhythm keeps the animals’ body clocks in step, so they feed, rest and breed normally and with far less stress.

Where the water comes from

Every drop in this facility starts as clean seawater from the Gulf of Oman, then passes a full treatment train before it reaches the animals. Some of the kit here has a twin on the tank itself — a lamp, a skimmer, a filter, a pump — but it is doing a different job at each end, and the ↔ lines say which.

• Intake 300 m offshoreSeawater is drawn from an intake about 300 m out to sea, away from the shoreline where run-off and sediment collect.
• Intake depthThe seabed here sits about 16 m down at low tide; the intake head is set at roughly 14 m at low tide — deep enough to draw cool, clean water yet held clear of the bottom.
• Below the thermoclineThe intake sits below the thermocline — the cooler, more stable deep layer — which also lowers the risk of drawing in a surface oil spill.
• Raised above the seabedAt about 14 m it is held roughly 2 m clear of the ~16 m bottom, so it does not pick up settled tar, silt or other bottom deposits.
• Pneumatic (air-driven) pumpsAir-driven pumps lift the seawater gently, with no oil-lubricated parts that could contaminate it.↔ These lift the water once, from the sea to the shore. Here gentleness matters more than pressure, which is why they are air-driven.
• Hydrocarbon analyserAn in-line hydrocarbon analyser continuously checks the incoming water and shuts the intake if any trace of oil is detected.
• Transfer pumpsTransfer pumps move the screened seawater one way — from the intake, ashore, into the treatment train.↔ Transport, not circulation — this water is on a one-way trip from the intake into the treatment train, and it makes it only once.
• Mechanical filtrationAny open-sea intake also draws in sand, silt, plankton and larvae; graded particle filters take those out first, so nothing downstream has to work through the sea floor.↔ At the intake this is coarse, high-volume work on genuinely dirty water: sea-floor sand and whole plankton, at the full intake flow.
• UV sterilisationUltraviolet light disinfects the incoming seawater, so nothing living that came in with it — bacteria, parasites, drifting larvae — carries on into the facility.↔ On the way in this is a single pass: each litre of raw seawater crosses the lamp once, at full intake flow, so whatever the Gulf was carrying that day never reaches a tank.
• Temperature controlThe sea outside swings with the season, from cool winter water to well over 30 °C in a Gulf summer. The incoming water is brought to one standard holding temperature before it goes anywhere near an animal.↔ At the intake this is a one-off correction to a large batch: whatever temperature the sea happened to be that day, brought to one standard before storage.
• Protein skimmingFoam-fractionation strips out the dissolved organics and any residual oils and surfactants the seawater arrived with, before it goes into storage.↔ At the intake the skimmer deals with what the sea brought in: dissolved organics and any oily residue, taken out once, before storage.
• AerationAeration re-oxygenates the water and off-gasses unwanted volatile compounds.
• Ozone sterilisationA final ozone treatment gives a powerful disinfection and improves water clarity before storage.
• DistributionThe treated seawater is then distributed to the laboratory systems and the display aquarium.

Sources & references

The species information here is drawn from published research — see the Bibliography for full detail.

• Diet & natural prey
  Each species’ wild diet is researched from published feeding studies and FishBase, then matched to the food groups used here — full detail in the Bibliography. · source ↗
• IUCN conservation status
  Red List category taken from the IUCN Red List of Threatened Species. · source ↗
• Zoological classification
  Kingdom-to-species from the Catalog of Fishes / FishBase (fishes) and WoRMS (invertebrates). · source ↗
• Native range
  Distribution mapped from FishBase / SeaLifeBase species summaries. · source ↗
• Bald glassy (Ambassis gymnocephalus)
  Martin & Blaber — Feeding ecology of Ambassidae in Natal estuaries (S. Afr. J. Zool.) · source ↗
• Black-spotted butterflyfish (Chaetodon nigropunctatus)
  FishBase — Ecology; Wikipedia (C. nigropunctatus) · source ↗
• Bluetail trunkfish (Ostracion cyanurus)
  Feeding habits of O. meleagris (congener) — colonial ascidians; Ostraciidae reviews · source ↗
• Horseshoe butterflyfish (Chaetodon pictus)
  Animal Diversity Web — Chaetodontidae (family) · source ↗
• Sergeant Major (Abudefduf saxatilis)
  Bonaldo et al. — Diel feeding activity of A. saxatilis (SciELO, Neotropical Ichthyology) · source ↗
• Silver moony (Monodactylus argenteus)
  Estuarine diet notes + aquarium husbandry references (aggregated) · source ↗
• White-spotted rabbitfish (Siganus canaliculatus)
  Gut Content Analysis of S. canaliculatus (IJRIAS); Feeding habits & reproductive biology (CMFRI) · source ↗
• Blue-barred / yellowscale parrotfish (Scarus ghobban)
  FishBase summary (Scarus ghobban); IUCN Red List; Scaridae feeding studies · source ↗