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Shoal & Stem

Flora & Fauna

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

fish
easy

Gold Tetra

Hemigrammus rodwayi

fishfreshwater

The gold tetra has a distinctive golden-yellow sheen to the body caused by a parasitic infection the fish experiences in the wild — this actually produces the attractive gold iridescence that hobbyists prize. Tank-bred specimens often lack the intense gold but retain a pleasant iridescence. A peaceful, undemanding schooling fish.

fish
easy

Golden Pencilfish

Nannostomus beckfordi

fishfreshwater

Hardy, golden-bodied pencilfish with a bold red-and-black lateral stripe. The most adaptable pencilfish — tolerates a wider pH range than most. Great for beginner planted tanks.

fish
moderate

Gossei Corydoras

Corydoras gossei

fishfreshwater

Gossei corydoras is a medium-sized species with a golden-tan body adorned with irregular dark markings. It is sometimes called the tail spot cory for the dark blotch at the caudal peduncle. A peaceful schooling species that does well in South American biotope setups with dark substrate and tannin-stained water.

fish

Green Corydoras

Corydoras aeneus

fishfreshwater
algae
medium

Green Dust Algae

Chlorophyta (various)

algaefreshwater

Fine, powdery green coating on the glass that wipes off easily but returns quickly. Different from Green Spot Algae — much softer and more responsive to physical removal. A large clean-up crew (nerites, Mystery snails, Otocinclus) keeps it in check. Usually a sign of moderate light excess.

shrimp
easy

Green Jade Shrimp

Neocaridina davidi var. 'Green Jade'

shrimpfreshwater

Green jade shrimp are a selectively bred Neocaridina variety with an opaque mint-green colour. Like all Neocaridina they are hardy and tolerate a wider range of water conditions than Caridina. Their unique green colouration is particularly striking against dark substrate.

shrimp
easy

Green Jade Shrimp

Neocaridina davidi var.

shrimpfreshwater

Opaque jade-green Neocaridina with excellent colour contrast in planted tanks. Rarer than the red and blue variants. As hardy and prolific as all other Neocaridina — a great addition to any shrimp collection.

fish

Green Laser Corydoras

Corydoras sp. 'CW009'

fishfreshwater
fish
moderate

Green Neon Tetra

Paracheirodon simulans

fishfreshwater

The green neon tetra is the smallest of the three Paracheirodon tetras and one of the most underappreciated. It has a longer, more vivid blue-green stripe with a shorter red patch compared to the cardinal tetra. It is a strict blackwater species requiring soft, very acidic water and is best kept in biotope setups with tannin-stained water and low light.

algae
medium

Green Spot Algae

Coleochaete orbicularis

algaefreshwater

Hard, dark green circles on glass and slow-growing plant leaves — familiar to virtually every planted tank keeper. Caused by low phosphate (counterintuitively) and high light. Nerite snails are the most effective control. A small amount is considered normal and harmless.

fish
medium

Green Terror Cichlid

Andinoacara rivulatus

fishfreshwater

Green terror cichlids are large, dramatic fish with vivid turquoise-green scaling and orange-edged fins. Males develop a pronounced nuchal hump with age. Despite the name, they are manageable in species or large community cichlid setups.

algae
medium

Green Water (Algae Bloom)

Chlorella / Euglenoids

algaefreshwater

Pea-soup green tank water caused by a bloom of free-floating unicellular algae. Usually triggered by a combination of high nutrients and direct sunlight. A UV steriliser will clear it within days. A 3-day blackout is an alternative. Daphnia (water fleas) can be added to a fishless tank as biological control.

fish
easy

Guppy

Poecilia reticulata

fishfreshwater

Guppies are hardy, colourful livebearers that reproduce readily in captivity. Males display elaborate tails and body patterns to attract females. They adapt to a wide range of water conditions, though clean, well-filtered water is essential to prevent fin disease.

plant
easy

Guppy Grass

Najas guadalupensis

plantfreshwater

Known as Guppy Grass or Najas Grass, this fast-growing, fine-leaved plant is a superb filtration plant and spawning medium. It floats freely or can be weighted down. Its vigorous growth absorbs excess nutrients, helping combat algae. Very tolerant of a wide range of water conditions.

plant
hard

HC Cuba

Hemianthus callitrichoides

plantfreshwater

Hemianthus callitrichoides 'Cuba' (HC Cuba) holds the record as the smallest-leaved aquatic carpeting plant, with each leaf barely 0.5 mm across and stems rarely exceeding 3 cm. Under optimal conditions of high light, CO2, and soft water it forms an impossibly dense, bright-green lawn that is the holy grail of foreground carpets in aquascaping. Extremely demanding and unforgiving of parameter fluctuations, it is best suited to experienced, high-tech setups.

algae
medium

Hair Algae

Oedogonium sp.

algaefreshwater

Fine, bright-green strands that drape over plants and hardscape. One of the most common new-tank algae — usually caused by excess light, nutrient imbalance, or lack of fast-growing plants competing for nutrients. Nerite snails, Amano shrimp, and Florida Flagfish make short work of it.

plant
easy

Hairy Marsilea

Marsilea hirsuta

plantfreshwater

Marsilea Hirsuta is a low-maintenance carpet plant that produces small, clover-like leaves on short stems. It spreads via runners to form a lush, medium-height green carpet without requiring CO2 injection — making it one of the easiest carpet plants for low-tech tanks. Leaves grow taller without CO2 but stay compact with it.

fish

Haraldschultzi Corydoras

Corydoras haraldschultzi

fishfreshwater
fish
easy

Harlequin Rasbora

Trigonostigma heteromorpha

fishfreshwater

The harlequin rasbora is recognised by the distinctive black triangular patch on its rear half set against a copper-orange body. Hardy, peaceful, and active in the midwater, it pairs beautifully with planted tanks.

fish

Hastatus Corydoras

Corydoras hastatus

fishfreshwater
plant
medium

Hemianthus Glomeratus

Hemianthus glomeratus

plantfreshwater

A delicate stem plant with tiny, round-to-oval bright green leaves growing in whorls of 3–4 around thin stems. Often confused with H. micranthemoides but has slightly larger leaves and a more upright growth habit. Grows quickly with CO₂ and high light, producing dense, bushy clumps that work well as a background planting. Without CO₂ it grows slowly and may become leggy. Regular trimming encourages compact, lush growth.

fish
medium

Hillstream Loach

Sewellia lineolata

fishfreshwater

The Hillstream Loach (Reticulated Hillstream Loach) is a spectacularly patterned torrent fish with a flattened body and enlarged pectoral fins adapted for clinging to rocks in fast-flowing streams. In the aquarium it requires strong water movement, high oxygenation, and cool temperatures mimicking its native Vietnamese mountain streams. It grazes periphyton (algae and biofilm) from hard surfaces and benefits from supplemental feeding with blanched vegetables and spirulina wafers.

fish
medium

Hockey Stick Pencilfish

Nannostomus eques

fishfreshwater

Distinctive pencilfish that swims at a 45° upward angle with its head tilted toward the surface. Copper-red body with a bold black lateral stripe. Fascinating schooling behaviour in planted tanks.

fish
easy

Honey Gourami

Trichogaster chuna

fishfreshwater

The Honey Gourami is one of the most peaceful labyrinth fish in the hobby — males develop a rich golden-honey coloration with an orange-red throat and belly when in breeding condition. At 4–5 cm it fits comfortably in nano and small community tanks. Less prone to disease than the Dwarf Gourami and considerably more tolerant of soft, acidic water, making it an excellent alternative for low-tech planted setups.

fish
medium

Hongsloi Dwarf Cichlid

Apistogramma hongsloi

fishfreshwater

Striking apisto with vivid yellow, red, and blue colouring on males. Highly variable in colour intensity depending on mood and water quality. A showpiece fish for any planted South American biotope.

snail
easy

Horned Nerite Snail

Clithon corona

snailfreshwater

The Horned Nerite is a small, striking nerite species notable for its ornate shell decorated with irregular blunt horn-like protrusions that vary in number, length, and arrangement between individuals — no two are quite alike. Like other nerites it is an excellent algae grazer and cannot reproduce in freshwater, so populations remain controlled. The unusual shell adds unique sculptural texture to planted tanks and nano aquariums.

plant
easy

Hornwort

Ceratophyllum demersum

plantfreshwater

Hornwort is one of the most adaptable aquatic plants available, surviving in a wide range of conditions from cold ponds to tropical tanks. It requires no substrate and can float or be anchored. It grows rapidly, absorbing nutrients, and provides excellent cover for fry.

fish
easy

Horsefaced Loach

Acantopsis dialuzona

fishfreshwater

Elongated loach with a distinctive long snout for sifting sand. Spends much of its time buried with just its eyes visible. Peaceful and an excellent sand-bed cleaner.

plant
easy

Hydrocotyle Japan

Hydrocotyle sp. 'Japan'

plantfreshwater

A compact variant of pennywort that produces small, neatly round, bright green leaves on short stems. Unlike the faster-growing H. tripartita, it has a more controlled growth habit and can be used as a delicate foreground or mid-ground filler. It adapts readily to CO2 and non-CO2 tanks alike.

plant
medium

Hydrocotyle Tripartita

Hydrocotyle tripartita

plantfreshwater

Hydrocotyle tripartita is a fast-growing stem plant with unique three-lobed leaves that create a lush, dense carpet or mid-ground cluster. With CO2 and high light it forms tight mounds. Without CO2 it grows taller and more open. Very popular in aquascaping.

plant
easy

Hygrophila 'Bold'

Hygrophila sp. 'Bold'

plantfreshwater

A robust cultivar with unusually wide, wavy-edged leaves that give a bold, architectural presence in the background. The large leaf surface collects bubbles during pearling, making it a favourite for photography. Very easy to grow and tolerant of low-tech conditions.

plant
easy

Hygrophila 'Sunset'

Hygrophila sp. 'Sunset'

plantfreshwater

A variegated cultivar with creamy white, pink, and green patterning on the leaves — the colours intensify under stronger light. A favourite in Dutch and community planted tanks for adding colour without the difficulty of true red plants. Stays compact and bushy with regular trimming.

plant
easy

Hygrophila Angustifolia

Hygrophila angustifolia

plantfreshwater

A narrow-leaved Hygrophila with long, willowy green leaves held in whorls along upright stems. Grows faster than most Hygrophila species and provides a graceful, flowing texture in the background. The fine leaf texture contrasts well with broad-leaved plants like Anubias or Cryptocoryne. Easy to grow in most conditions — one of the few Hygrophilas that maintains its narrow, elegant leaf form even in low tech.

plant
medium

Hygrophila Araguaia

Hygrophila lancea 'Araguaia'

plantfreshwater

A striking stem plant with ultra-narrow, needle-like leaves that turn deep red-purple under high light and CO₂. The fine, dense foliage creates a delicate, feathery texture rarely seen in other stem plants. Grows quickly and benefits from regular trimming to maintain a bushy appearance. The colour is highly dependent on light intensity — low light produces mostly green growth. One of the most popular plants in competitive aquascaping.

plant
easy

Hygrophila Corymbosa Compact

Hygrophila corymbosa 'Compact'

plantfreshwater

A cultivar of the Temple Plant with shorter internodal spacing, producing a denser, bushier plant than the standard species. Large, bright green leaves are held close to the stem, giving it a robust, architectural look in the midground or background. One of the easiest stem plants to grow — thrives in low-tech tanks and is very forgiving of neglect. A great beginner plant that still looks impressive in mature scapes.

plant
medium

Hygrophila Pinnatifida

Hygrophila pinnatifida

plantfreshwater

A standout aquascape plant with oak-like lobed leaves that are dark green on top and purple-red beneath. Unlike most Hygrophilas it can be attached to hardscape like Anubias. Under high light and CO2 the purple coloration intensifies dramatically, making it one of the most visually striking stem plants available.