Moonlight Gourami Care Guide

The moonlight gourami is a large, silvery, genuinely peaceful gourami that is shy to the point of being skittish — sold as a small community fish, it actually wants a big, calm, heavily planted tank where it can feel hidden, and it carries the longest thread-like 'feelers' of any gourami.

Moonlight Gourami at a glance

The sourced figures the welfare engine uses to judge Moonlight Gourami — the parseable key facts.

Where it comes from

Trichopodus microlepis comes from the lowland ponds, bogs and swamps of the Mekong basin (Cambodia, Vietnam) and the Chao Phraya basin (Thailand), the kind of still, shallow, sun-warmed water where aquatic and marginal vegetation grows densely. That biotope writes the whole care sheet. Standing, vegetated water means low flow and a heavily planted tank with surface cover; strong current stresses it. Oxygen-poor swamp water means a labyrinth organ, so FishBase classes it as an obligate air-breather that must reach the surface to gulp atmosphere. And a shaded, plant-choked home means a fish that wants dim, diffuse light and dense refuge — drop it into a bare, bright tank and a newly added fish will often hide for days or even weeks and stay washed-out. Its soft, slightly acidic origins mean it looks and breeds best in soft, slightly acidic, warm water, though tank-bred stock is broadly adaptable.

Did you know?

• It glows 'moonlight': the plain silvery body carries a fine iridescent green-blue sheen that deepens with maturity, the source of every trade name — Moonlight, Moonbeam, Silver.
• It has the longest 'feelers' of any gourami: Seriously Fish notes its modified thread-like ventral fins are considerably longer than in other gourami species, trailed over surroundings as touch-and-taste organs.
• It breathes air through a labyrinth organ and is classed by FishBase as an obligate air-breather — an adaptation to oxygen-poor swamp water.
• Males blush red to breed: the clearest sex difference is the male's orange-to-red pelvic fins versus the female's yellow.
• A prolific bubble-nest dad — a single spawn can yield up to roughly 2,000 eggs, which the male then guards.
• Its upward-sloping, concave forehead is a quick field-ID trait separating it from other silvery Trichopodus.
• FishBase lists it as IUCN Least Concern (assessed 2011) — a widespread, common Southeast Asian swamp fish and a minor food/aquaculture species in parts of its range.

Tank size — and why

This is the load-bearing point: the moonlight is a large gourami of about 13-15 cm (Seriously Fish gives a 15 cm maximum, FishBase 14 cm TL, and most aquarium specimens settle around 12-13 cm), far bigger than the dwarf and honey gouramis it sits beside in shops. About 30 US gallons (roughly 114 L) is the practical floor for one fish or a pair — Seriously Fish frames this as a 36 x 12 x 12 inch base footprint, a 3-foot tank — and 40-50 gallons-plus is better for a small group. Footprint matters more than raw volume: it needs swim length, open surface area for an air-breather working the top of the tank, water to dilute a medium bioload, and horizontal space so a shy fish (and territorial males) can break sightlines. It is tall-bodied, so reasonable height plus a long footprint suits it, but prioritise length and surface area over a narrow column.

As a guide, a 30-gallon tank comfortably suits about 1 Moonlight Gourami as a single-species display, leaving room for tankmates.

How big does it really get?

Full-grown Moonlight Gourami reach about 15 cm (5.9 in) long, but they are usually sold at only about 3 cm (1.2 in) — a typical shop size (estimate). At full size, Moonlight Gourami needs roughly a 30-gallon tank, about 76 cm long; a common 10-gallon starter kit is only about 51 cm.

Adult size is sourced; the shop size is a typical-juvenile estimate; tank length is approximate for a standard 30-gallon aquarium.

Water parameters in practice

Treat 25-30 °C as the husbandry target; the recommended band stays warm (FishBase 26-30 °C, Seriously Fish 25-30 °C), though a couple of care guides cite tolerated lows of 22-24 °C. pH 6.0-7.5 is ideal, with FishBase narrower at 6.0-7.0, and hardness is forgiving from soft to moderately hard (about 2-25 dH). Tank-bred moonlights are broadly tolerant of pH and hardness, so a cycled, stable, warm tank matters far more than chasing an exact number. Soft, slightly acidic, tannin-stained water best mirrors the wild swamp and supports spawning.

Diet & feeding

In the wild it is an omnivore leaning carnivore, taking zooplankton, crustaceans and aquatic insects in the vegetated swamp. In the tank it is unfussy and accepts most foods: a quality flake or pellet staple plus live or frozen bloodworm, mosquito larvae, blackworm, brine shrimp and daphnia, with some vegetable matter. Feed small amounts two or three times a day, only what is cleared in a minute or two, and watch out for overfeeding given its medium waste output. It trails its long ventral filaments over plants, food and tankmates to taste and feel its way around.

Gear & setup

Provide a heater, a cycled tank and gentle filtration (sponge or baffled), keeping flow low to mirror the still swamp. Plant heavily and add floating plants — frogbit, salvinia, water lettuce — to diffuse the light and give this skittish fish security and bubble-nest anchorage; dim, dappled light and dense cover are husbandry here, not decoration. Keep the tank covered but leave a warm, humid air gap above the water and do not fill to the brim: the labyrinth organ needs surface air, and gouramis jump.

Temperament & behaviour

Repeatedly described as a calm, elegant, peaceful community gourami, but genuinely timid and skittish. It works the mid-to-upper column and visits the surface to breathe, and in a bare, bright or busy tank it withdraws, fades and can hide for weeks. Males turn territorial with one another as they mature — Aquarium Tidings calls them 'incredibly territorial' — and can harass during breeding, so same-species friction is real among males even though it is nothing like betta lethality. Give it cover, dim light and calm tankmates and it settles and colours up.

Group & social needs

Not an obligate shoaler. A lone fish, a pair, or a small group with one male and several females all work; it does well in a calm group given space. The constraint is multiple males, which become territorial as they mature and want a bigger, broken-up tank (45 gallons-plus) so subordinate fish can escape sightlines. Keep a single male, or give several males room and refuge.

Compatible tank mates (preview)

A short, engine-cleared shortlist — the species TankStocking's welfare engine clears with Moonlight Gourami and that suit its size and temperament best. Tap any to load the pairing in the planner.

• Bamboo Shrimp (Wood/Fan Shrimp) — Peaceful temperament, similar adult size, not a fin-nipper.
• Boesemani Rainbowfish — Peaceful temperament, similar adult size, not a fin-nipper.
• Bolivian Ram — Peaceful temperament, similar adult size, not a fin-nipper.

A note on the shrimp and snails here: Moonlight Gourami is peaceful and generally invertebrate-safe — but almost any fish will take very small shrimplets given the chance, so give shrimp dense cover (moss, leaf litter) if you want a colony to grow, rather than expecting every baby to survive.

This engine-cleared shortlist is Moonlight Gourami's tankmate surface for now — a dedicated tank-mates guide can follow for high-demand species.

Breeding & sexing

Sexing is clear in mature fish: males develop orange-to-red pelvic fins and a longer, pointed dorsal, while females keep yellow or colourless pelvic fins, a shorter rounded dorsal and a fuller, rounder belly. The long thread-like ventral feelers are present in both sexes and are not a sexing cue. Breeding is rated intermediate and follows the classic bubble-nest pattern. Condition on live or frozen foods, then set up a separate breeding tank with a lowered water level, soft, slightly acidic water, a raised temperature around 27-28 °C and floating plants. The male builds a surface nest (about 4-5 inches across), wraps around the female under it, collects and places the eggs, then guards them — remove the female afterwards, as males get rough. Fecundity is very high, up to roughly 2,000 eggs per spawn; eggs hatch in about one to three days and fry are free-swimming a further five to seven days later. Fry rely on gills until the labyrinth organ develops, so keep them warm, humid and tightly covered, feeding infusoria or green water, then rotifers and baby brine shrimp.

Lifespan

About 4-5 years is the most-cited figure, with up to roughly 6 years reported and the occasional unconfirmed claim beyond that; FishBase publishes no maximum-age field for the species. What shortens it is poor or unstable water quality, chronic stress from a too-small, bare or bright tank, aggressive or nippy tankmates, cold or unstable temperature, and the opportunistic parasites and infections labyrinth fish are prone to.

Common mistakes

• Underestimating its size and space: it is a large gourami (about 13-15 cm), far bigger than dwarf and honey gouramis, and needs roughly 30 gallons-plus and a 3-4-foot footprint, not a nano tank.
• Using a bright, bare tank, when floating plants, dim diffuse light and dense cover are what stop a skittish fish hiding for weeks and losing colour.
• Overfilling the tank or skipping the surface air gap, when an obligate air-breather must reach humid surface air.
• Housing it with fin-nippers like tiger barbs or serpae tetras, which shred its fine fins and the longest feelers of any gourami.
• Keeping it with very small or boisterous fish, which may be bullied or eaten, or which bully this shy species into hiding.
• Crowding multiple males into too small a tank instead of keeping one male or giving several males a 45 gallon-plus, broken-up tank.
• Letting water go cold or unstable, which triggers ich, velvet and fin rot.

Signs of trouble

• Hiding and withdrawal, and faded colour, in a fish that should be out once settled.
• Clamped fins and lethargy.
• Appetite loss.
• Flashing or rubbing against surfaces.
• White spots (ich) or a fine gold/rust 'dusting' (velvet).

Is this fish right for you?

Don't buy this fish if you can't provide a heated, cycled 30 gallon-plus planted tank with cover, dim light, a surface air gap and a calm community. It is a large, shy centrepiece fish, not a nano or bowl fish and not a first-week-of-the-hobby pick for a small tank. It is fairly hardy once set up, so the main avoidable risks are cold or unstable water and rough or nippy tankmates rather than the fish itself. No source flags it as a primary iridovirus reservoir the way the inbred dwarf gourami is, but no source affirmatively clears it either, so don't mix it with suspect dwarf gourami stock and buy healthy, well-coloured fish.

Common questions

How big a tank do moonlight gouramis need?

About 30 gallons is the floor for one fish or a pair, with 40-50 gallons-plus and a 3-4-foot footprint better for a group, and 45 gallons-plus if you keep more than one male. They are large gouramis (~13-15 cm) that need swim length and open surface, not a nano tank.

Why is my moonlight gourami so shy and always hiding?

It is a genuinely timid, skittish species. Newly added fish often hide for days or weeks, and any moonlight stays withdrawn and washed-out in a bare, bright or busy tank. Heavy planting, floating cover and dim diffuse light are what bring it out.

How big do moonlight gouramis get?

About 13-15 cm. Seriously Fish gives a 15 cm maximum and FishBase 14 cm TL, with most aquarium fish settling around 12-13 cm — much larger than dwarf or honey gouramis.

Can I keep moonlight gouramis with tiger barbs or other nippers?

No. Fin-nippers such as tiger barbs and serpae tetras shred its fine fins and its long ventral feelers, which causes stress and infection. Choose calm, non-nippy tankmates.

How can I tell a male from a female moonlight gourami?

Look at the pelvic fins: mature males have orange-to-red pelvic fins and a longer, pointed dorsal, while females keep yellow or colourless pelvic fins, a rounder dorsal and a fuller belly. The long thread-like feelers are on both sexes.

Can I keep more than one moonlight gourami together?

Yes, but mind the males. A single fish, a pair, or one male with several females all work; multiple males turn territorial as they mature and need a bigger, broken-up tank (45 gallons-plus) so they can break sightlines.

Sources & confidence

Sources & confidence (9 species)

These back the Moonlight Gourami figures and the previewed tank mates above. Each figure is read from the TankStocking species database (v2026.06); below is the care reference behind it and how confident we are in that data. Confidence reflects the source quality, not whether any pairing is safe. Full source list and the welfare model are on the methodology page.

• Moonlight Gourami Trichopodus microlepis — Seriously Fish (seriouslyfish.com/species/trichopodus-microlepis) high confidence
• Bamboo Shrimp (Wood/Fan Shrimp) Atyopsis moluccensis — Aquariadise (aquariadise.com/caresheet-bamboo-shrimp-atyopsis-moluccensis) high confidence
• Boesemani Rainbowfish Melanotaenia boesemani — Seriously Fish; Aquarium Co-Op Boesemani guide high confidence
• Bolivian Ram Mikrogeophagus altispinosus — Seriously Fish (seriouslyfish.com/species/mikrogeophagus-altispinosus) high confidence
• Brilliant Rasbora Rasbora einthovenii — Seriously Fish (seriouslyfish.com/species/rasbora-einthovenii) high confidence
• Bristlenose Pleco Ancistrus sp. — Aquarium Source / aqua-fish.net Ancistrus care guides high confidence
• Clown Pleco Panaqolus maccus — Fish Laboratory (fishlaboratory.com/fish/clown-pleco); AquariumStoreDepot high confidence
• Congo Tetra Phenacogrammus interruptus — Seriously Fish (seriouslyfish.com/species/phenacogrammus-interruptus) high confidence
• Dwarf Gourami Trichogaster lalius — Seriously Fish (seriouslyfish.com/species/trichogaster-lalius) high confidence

Care-guide sources (7)

This guide synthesises the references below; where they disagree, the range and the disagreement are noted in the text above. The figures in the key-facts box are read from the TankStocking species database (v2026.06). Full welfare model on the methodology page.

• Seriously Fish — Trichopodus microlepis
• FishBase — Trichopodus microlepis
• Aquadiction — Moonlight Gourami
• Aquarium Tidings — Moonlight Gourami
• Aqua-Fish.net — Moonlight Gourami
• Fishkeeping World — Moonlight Gourami
• Tropical Fish Hobbyist — Lunar Beauties: Moonlight Gouramis

More on Moonlight Gourami

Related guides on TankStocking — each scored by the same welfare engine as the planner.

This care guide is a sourced planning reference, not veterinary advice — individual fish, filtration and maintenance all matter. Cycle the tank, test your water, and observe your fish. How TankStocking works →