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Shoal & Stem

Flora & Fauna

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

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Koi Angelfish

Pterophyllum scalare

fishfreshwater

A captive-bred colour morph with a bold red-orange, white, and black marbled pattern reminiscent of koi pond fish. Each individual is uniquely marked. Hardy and one of the most popular angelfish varieties in the hobby. Same care requirements as other P. scalare varieties.

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easy

Kole Tang

Ctenochaetus strigosus

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Brown tang covered with fine yellow-orange spots. Excellent detritivore and algae grazer. More peaceful and compact than most tangs. Great reef fish.

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easy

Kribensis

Pelvicachromis pulcher

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The Kribensis is an attractive, personable West African dwarf cichlid from Nigerian coastal rivers and one of the most beginner-accessible cichlids available. Both sexes are colourful — females develop a bright cherry-red belly when in breeding condition. Pairs form strong bonds and jointly guard fry in caves, making them fascinating to observe. They are tolerant of a wide range of water conditions and generally peaceful outside of breeding territory.

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easy

Kuhli Loach

Pangio kuhlii

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The Kuhli Loach is an eel-like, nocturnal loach from Southeast Asia with alternating yellow-orange and dark-brown banding. It wriggles through substrate and around plant roots searching for food, making it a fascinating and useful bottom-level scavenger. Kuhli Loaches are social and do best in groups of five or more; lone individuals are shy and rarely seen. Fine sand is essential to protect their sensitive underbellies.

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Laguna de Patos Endler

Poecilia wingei

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easy

Lake Kutubu Rainbowfish

Melanotaenia lacustris

fishfreshwater

The Lake Kutubu rainbowfish is one of the most intensely coloured species in the genus. Males develop a vivid turquoise-blue upper body that grades to silver-yellow on the lower flanks. It is a robust, active fish suited to larger planted or Dutch-style aquariums. The intense colouration only develops fully in mature males in well-maintained water.

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easy

Lake Tebera Rainbowfish

Melanotaenia herbertaxelrodi

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Lake Tebera rainbowfish is a medium-sized species with males displaying a yellow-gold body with a reddish-orange upper flank and vivid red fins. It is a hardy, colourful rainbowfish that is easy to breed and well suited to community tanks with other peaceful species. Its bright colouration intensifies significantly during spawning courtship.

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easy

Lambchop Rasbora

Trigonostigma espei

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The lambchop rasbora has a slimmer body than the harlequin rasbora with a characteristically narrow, wedge-shaped black mark on the rear half. Peaceful and undemanding, it is ideal for nano planted tanks and pairs beautifully with shrimp.

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medium

Laser Corydoras

Corydoras sp. 'CW010'

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The laser corydoras (orange laser or green laser depending on the variant) has a striking iridescent stripe running the length of the body. These undescribed species are highly sought after by corydoras enthusiasts and require soft, warm water.

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easy

Lawnmower Blenny

Salarias fasciatus

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The go-to algae control fish for reef tanks — relentlessly grazes film algae and hair algae off rocks and glass. Camouflaged brown-grey with warty skin and charismatic perching behaviour.

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easy

Least Killifish

Heterandria formosa

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One of the smallest vertebrates in the world — females reach just 1.5 inches. A fascinating livebearer from the USA that thrives in cool, planted nano tanks. Ideal for a species setup.

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Lemon Cichlid

Neolamprologus leleupi

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Brilliant yellow Tanganyikan cichlid that lives in rocky crevices. Curious and bold but aggressive toward its own kind. Stunning in a rock-heavy Tanganyika biotope.

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easy

Lemon Tetra

Hyphessobrycon pulchripinnis

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The lemon tetra is a classic, elegant fish with a translucent lemon-yellow body, vivid yellow dorsal and anal fins edged in black, and striking red eyes. It is a hardy, peaceful schooling fish that has been in the hobby for decades. The intensity of yellow colouration deepens considerably under warm, high-quality lighting in a planted tank.

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Leopard Danio

Danio rerio var. frankei

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hard

Leopold's Angelfish

Pterophyllum leopoldi

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The smallest and rarest Pterophyllum species. Distinguishable from P. scalare by its more elongated body, a distinctive black spot on the dorsal base, and an absence of the pre-dorsal notch. Rarely available in the trade and best kept by experienced keepers. Requires soft, acidic conditions similar to the altum.

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Leucomelas Corydoras

Corydoras leucomelas

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Longfin Zebra Danio

Danio rerio

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easy

Longnose Hawkfish

Oxycirrhites typus

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Instantly recognisable by its elongated snout and white body with red grid pattern. Perches in gorgonian sea fans and black coral, propping itself on its fins. Bold and long-lived in captivity.

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Loxozonus Corydoras

Corydoras loxozonus

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easy

Lubbock's Fairy Wrasse

Cirrhilabrus lubbocki

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Strikingly colourful — males flash vivid red, orange, and yellow with iridescent highlights during display. Peaceful and active; best kept as one male with several females. A jewel of the mid-water column.

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Lyretail Anthias

Pseudanthias squamipinnis

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One of the most colourful reef fish — females orange-pink, males dazzling magenta-purple with elongated tail filaments. Best kept in a harem (one male, multiple females) with strong flow and frequent feeding.

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Macropterus Corydoras

Corydoras macropterus

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intermediate

Mahachai Betta

Betta mahachaiensis

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Betta mahachaiensis is a wild betta discovered in 2012 in the brackish coastal habitats of Samut Sakhon, Thailand — making it unique among bettas in its tolerance for slightly saline conditions. Males display striking iridescent teal-blue scale edging similar to B. smaragdina. It builds bubble nests and is less aggressive than B. splendens toward other species. Its restricted wild range makes it important for conservation-minded hobbyists.

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Malabar Danio

Devario malabaricus

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expert

Mandarin Dragonet

Synchiropus splendidus

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Arguably the most beautiful fish in the hobby. Requires a mature reef with abundant copepods. Not for beginners. Will starve if not given live food.

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Marble Angelfish

Pterophyllum scalare

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A captive-bred variety with a swirling black-and-white marbled pattern caused by the marble gene. The pattern is unpredictable and no two fish look alike. One of the most widely kept angelfish morphs, well suited to planted scapes.

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Marble Betta

Betta splendens 'Marble'

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Marble Bettas carry a transposon-driven colour mutation discovered in the 1970s that causes random, irregular patches of pigmentation. One of their most fascinating traits is colour instability — a marble betta can spontaneously change colour pattern over its lifetime as the transposon activates or silences pigment genes. This unpredictability makes every individual unique and constantly surprising to their owners.

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Marbled Hatchetfish

Carnegiella strigata

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Smallest hatchetfish with intricate brown-and-gold marbled patterning. A delicate but fascinating surface fish. Needs a very tight-fitting lid as it can jump significant distances.

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Maroon Clownfish

Premnas biaculeatus

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The largest clownfish species, maroon-red with bold white stripes. Highly aggressive — best kept as a single specimen or bonded pair. One of the most striking reef fish available.

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Melanistius Corydoras

Corydoras melanistius

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easy

Melanurus Wrasse

Halichoeres melanurus

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Dazzling rainbow colouration — females green-blue, males sporting a vivid magenta-and-green pattern. A sand-diver that buries to sleep. Natural predator of flatworms and pyramid snails.

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Midas Blenny

Ecsenius midas

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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.

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Molly

Poecilia sphenops

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Mollies are versatile livebearers available in many colour forms including black, dalmatian, and balloon. They are adaptable to a wide range of conditions including brackish water. Females give birth to live young and breed prolifically in captivity.

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Moonlight Gourami

Trichopodus microlepis

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Elegant silver gourami with a subtle moonlit sheen and orange-red ventral fins. One of the most peaceful and graceful labyrinth fish. Works beautifully in a tall, well-planted aquarium.

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Mosquito Rasbora

Boraras brigittae

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One of the smallest schooling fish in the hobby at just 0.8 inches. Deep red body with a black lateral spot. Thrives in blackwater planted nano tanks. Looks extraordinary in groups of 20+ against green plants.

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easy

Mosquitofish

Gambusia affinis

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Mosquitofish are exceptionally hardy, adaptable livebearers that have been deliberately introduced worldwide for mosquito larvae control. They consume prodigious quantities of surface larvae and can survive conditions — extreme heat, cold, salinity, low oxygen — lethal to most aquarium fish. Note that they are aggressive fin nippers and should not be housed with fancy-finned fish; they are best suited to utility or outdoor pond use rather than display aquariums.