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Shoal & Stem

Flora & Fauna

673 entries — care guides, placement tips, and notes from the community

algae
medium

Mermaid's Fan

Udotea flabellum

algaesaltwater

Elegant fan-shaped calcified macroalgae on a slender white stalk. Grows in sandy areas near reefs and seagrass beds. A beautiful decorative species for low-flow areas of the display tank. Like Penicillus, it anchors in deep sand and has a natural lifespan of several months.

algae
medium

Mermaid's Wine Glass

Acetabularia acetabulum

algaesaltwater

One of the most extraordinary organisms in biology — a single giant cell shaped like a wine glass on a slender stalk. Each 'plant' is a single cell that can grow to 10 cm. Famous in cell biology research. In aquariums it anchors in sand and is a remarkable conversation piece. Prefers cooler, calcium-rich water.

fish
easy

Midas Blenny

Ecsenius midas

fishsaltwater

Brilliant golden-yellow with a flowing, eel-like body. Often mimics Lyretail Anthias in colour. Perches on rockwork and darts into crevices when startled — reef-safe and entertaining to watch.

coral
hard

Montipora

Montipora sp.

coralsaltwater

Montipora is a diverse SPS coral genus second only to Acropora in species diversity, available in plating, branching, and encrusting growth forms in a wide array of colours. It is considered the entry-level SPS coral, more forgiving than Acropora but still demanding stable water parameters, high light, and good flow. Plating Montipora varieties are particularly popular for adding mid-level horizontal structure and bold colour to reef aquariums.

coral
easy

Mushroom Coral

Actinodiscus spp.

coralsaltwater

Mushroom corals (discosoma) are flat, fleshy soft corals available in a huge range of colours including green, blue, red, and metallic. They are excellent beginner corals, requiring low to medium light and tolerating nutrient-rich water better than SPS corals.

fish
medium

Mystery Wrasse

Pseudocheilinus ocellatus

fishsaltwater

Rare and stunning — white with bold yellow-outlined spots and red-tipped fins. A cryptic wrasse that stays hidden in the rockwork. Highly sought-after collector fish that commands a premium.

fish
medium

Naso Tang

Naso lituratus

fishsaltwater

Elegant tang with a characteristic orange-tipped rostrum, blue-trimmed fins, and long tail streamers in mature males. A graceful, active swimmer that needs a large tank. Excellent algae control.

snail
easy

Nassarius Snail

Nassarius sp.

snailsaltwater

Small sand-dwelling scavenger that buries itself and erupts from the substrate to feed on meaty detritus. Excellent sand bed aerator and clean-up crew staple.

algae
medium

Neomeris

Neomeris annulata

algaesaltwater

Tiny, elegant calcified algae with a barrel-shaped body ringed with white calcium bands at the tip. Short-lived (weeks to months) but reproduces readily in stable reef tanks. An interesting hitchhiker and occasional deliberate addition. Fish tend to leave it alone due to calcification.

fish
easy

Neon Goby

Elacatinus oceanops

fishsaltwater

Tiny electric-blue-striped goby renowned as a cleaner fish — will pick parasites from larger tank mates. Ideal for nano reefs. The Caribbean's answer to the cleaner wrasse.

fish
easy

Ocellaris Clownfish

Amphiprion ocellaris

fishsaltwater

The iconic clownfish made famous by Finding Nemo. Hardy, peaceful, and symbiotic with anemones. Excellent beginner saltwater fish.

coral
easy

Open Brain Coral

Trachyphyllia geoffroyi

coralsaltwater

Free-living LPS with dramatic maze-like ridges and vivid colours — green, red, blue, and multicolour morphs. Placed directly on sand; inflates impressively at night to feed. One of the most beautiful reef centrepieces.

fish
easy

Orchid Dottyback

Pseudochromis fridmani

fishsaltwater

Vivid orchid-purple throughout — one of the most coveted nano reef fish. A Red Sea endemic that is now tank-bred widely. Bold personality for its size; can be aggressive to smaller fish.

fish
easy

Pajama Cardinalfish

Sphaeramia nematoptera

fishsaltwater

Unmistakable with its yellow head, dark mid-band and polka-dotted orange rear — like a fish in pyjamas. Nocturnal schooler that hovers in groups near branching corals. Very peaceful and reef-safe.

coral
easy

Palythoa

Palythoa grandis

coralsaltwater

Large-polyped cousins of Zoanthids — drab tan-brown in the wild but cultivated morphs include greens, yellows, and reds. Hardy and fast-spreading. Contain palytoxin — handle with gloves. Excellent beginner coral.

algae
medium

Peacock's Tail

Padina pavonica

algaesaltwater

Fan-shaped brown-grey macroalgae with distinctive concentric rings and a lightly calcified surface. Grows on rock in moderate flow zones. Not commonly traded but attractive in display refugia. Tolerates a wide range of temperatures — found from Mediterranean rock pools to tropical reefs.

shrimp
easy

Peppermint Shrimp

Lysmata wurdemanni

shrimpsaltwater

Translucent shrimp with red stripes. Famous for eating Aiptasia pest anemones. An essential pest controller for reef tanks.

fish
easy

Pink Skunk Clownfish

Amphiprion perideraion

fishsaltwater

Pale pink-orange with a single white dorsal stripe and cheek bar. One of the smallest and most peaceful clownfish — ideal for nano reef tanks alongside Magnificent Anemones.

coral
medium

Pipe Organ Coral

Tubipora musica

coralsaltwater

Unique soft coral with a rigid, blood-red calcium carbonate skeleton and vivid green polyps. The skeleton resembles organ pipes — stunning when visible at the base. More demanding than most soft corals but worth the effort.

shrimp
easy

Pistol Shrimp

Alpheus randalli

shrimpsaltwater

Famous for its symbiosis with watchman gobies — the shrimp digs a burrow and the goby guards the entrance. Pairs perfectly with Yellow Watchman or Randall's Pistol Goby. Produces a loud snapping sound.

coral
medium

Pocillopora

Pocillopora spp.

coralsaltwater

Pocillopora is a branching SPS coral with densely packed round polyp heads giving it a cauliflower-like appearance. It is one of the more forgiving SPS corals for beginners to reef keeping, growing quickly under stable conditions. Available in green, pink, and purple morphs.

fish
medium

Porcupine Puffer

Diodon holocanthus

fishsaltwater

Endearing and personable puffer with large eyes and a round body covered in spines. Will eat inverts — FOWLR only. Develops a real personality and recognises its keeper.

coral
medium

Porites Coral

Porites lobata

coralsaltwater

Massively important reef-builder — slow-growing mounds and columns covered in tiny polyps. Host to Christmas Tree Worms and boring clams. Hardy for SPS; tolerates a wider range of conditions than Acropora.

fish
hard

Powder Blue Tang

Acanthurus leucosternon

fishsaltwater

One of the most beautiful tangs with a powder-blue body, yellow dorsal fin and black mask. Prone to ich and disease — best for experienced reef keepers.

coral
easy

Pulsing Xenia

Xenia spp.

coralsaltwater

Pulsing xenia is one of the most fascinating soft corals, rhythmically opening and closing its feathery polyps in a hypnotic pulse. It grows rapidly and can spread across rockwork quickly, so placement should be deliberate. Thrives in stable reef conditions.

fish
easy

Purple Firefish

Nemateleotris decora

fishsaltwater

One of the most visually striking nano reef fish — white to yellow body fading into vivid purple-magenta. Peaceful and reef-safe; will jump, so a tight lid is essential.

coral
medium

Purple Sea Fan

Gorgonia ventalina

coralsaltwater

The iconic purple fan-shaped gorgonian found throughout the Caribbean. Non-photosynthetic — requires regular target feeding with coral foods or phytoplankton. Grows in the plane perpendicular to current flow. A dramatic display piece.

fish
medium

Purple Tang

Zebrasoma xanthurum

fishsaltwater

Deep violet-purple with a bright yellow tail — one of the most desired tang species. A Red Sea endemic, now tank-raised. Aggressive toward other tangs so introduce with care.

algae
easy

Red Gracilaria

Gracilaria sp.

algaesaltwater

Bushy red-to-burgundy macroalgae prized as live food for herbivorous fish — tangs, rabbitfish, and urchins graze on it enthusiastically. Also an excellent nutrient exporter in refugia. Tumbles well under flow and tolerates a wide range of conditions.

algae
medium

Red Grape Algae

Botryocladia sp.

algaesaltwater

Rare and coveted — clusters of translucent, deep-red spherical bladders like bunches of miniature grapes. A showpiece macroalgae that attaches to live rock. Slow-growing and sensitive; requires stable, high-quality water. Highly sought after for display refugia and naturally deters herbivorous fish.

fish
expert

Regal Angelfish

Pygoplites diacanthus

fishsaltwater

Breathtakingly beautiful with alternating white-and-orange bars. Notoriously difficult to feed in captivity. Red Sea specimens generally adapt better than Pacific ones.

coral
easy

Ricordea Florida

Ricordea florida

coralsaltwater

Colourful mushroom coral covered in bumpy vesicles in shades of green, orange, and blue. Slower-growing than regular mushrooms. Hardy and great for beginners.

coral
easy

Ricordea Yuma

Ricordea yuma

coralsaltwater

The Indo-Pacific cousin of Ricordea florida — single-polyp mushroom with vivid nodular texture. Some of the most wildly colourful colourations in the hobby: electric blue, neon orange, purple, and multicolour. Highly collectible.

fish
easy

Royal Gramma

Gramma loreto

fishsaltwater

Arguably the most striking Caribbean reef fish — front half vivid purple, rear half bright yellow. Hardy, peaceful, and reef-safe. Tends to hang upside-down under ledges mimicking its cave habitat.

algae
medium

Sargassum

Sargassum natans

algaesaltwater

The iconic free-floating brown macroalgae of the open ocean — forms dense golden-brown mats in the Sargasso Sea. In aquariums it anchors to rock or tumbles freely. Hosts an entire ecosystem of cryptic animals (pipefish, frogfish, shrimp) in the wild. Challenging to keep long-term but impressive in large displays.

shrimp
medium

Saron Shrimp

Saron marmoratus

shrimpsaltwater

Beautifully mottled green and brown with long hairy appendages. Males develop an impressive brush of setae on their larger claw. Nocturnal and cryptic — hides by day but emerges at night. Can eat small invertebrates.