Freshwater Fish · Gouramis

Dwarf Gourami

Trichogaster lalius

Colourful labyrinth fish prone to farmed-stock diseaseIntermediate

Lifespan: 3-5 years
Size: 7-9cm
Social needs: Best singly or as a true pair; males clash
Time: Low-moderate
Cost: Low
Diet: Omnivore (flakes, pellets, frozen foods, some veg)

Overview

What is this animal?

The dwarf gourami is a small, brightly coloured labyrinth fish from the slow waters of South Asia, able to breathe air at the surface through a labyrinth organ.
Males are especially colourful in shades of blue and red.

Widely sold and inexpensive, they are nonetheless affected by farmed-stock health problems that catch out beginners, which places them at the intermediate level.
Calm and personable, they make good centrepieces for peaceful, planted community tanks when sourced carefully.

Temperament

Dwarf gouramis are generally peaceful and somewhat shy, but males can be territorial toward each other and toward similar-looking fish, so keep a single male or a genuine male-female pair rather than rival males.
They appreciate planted cover to retreat into.

Suitable tankmates include peaceful tetras, rasboras and corydoras; avoid fin-nippers and boisterous species that stress them.
Males may court and build bubble-nests.
Their calm disposition makes them a good community fish provided rival males and aggressive companions are avoided.

A good fit for

Peaceful planted community tanks
Keepers wanting a colourful surface-dweller
Those who research and source healthy stock
Aquarists with calm, low-flow setups

Common mistakes to avoid

Buying virus-prone mass-farmed stock
Keeping multiple rival males together
Strong flow stressing this calm-water fish
No lid, risking chilled labyrinth organ and jumping

Enclosure

Minimum 60 litres (16 US gallons)

Fine alone or with company. Best singly or as a true pair; males clash

Provide a planted tank of at least 60L with a calm water surface, warm at 24-28C and soft to moderately hard around neutral pH.
As air-breathers they need access to the surface, so avoid strong flow and keep a warm, humid air gap above the water.

Floating plants, gentle filtration and plenty of cover suit their shy nature.
Keep water well cycled with zero ammonia and nitrite.
A tight-fitting lid preserves the warm surface air their labyrinth organ relies on and prevents jumping.

Check your enclosure

Supplies

Setup

Tank and stand
Filter
Heater and thermometer
Substrate, plants and decor
Liquid test kit
Dechlorinator and starter supplies

Ongoing

Quality tropical flake
Floating and slow-sinking micro-pellets
Frozen bloodworm, brine shrimp and daphnia
Spirulina or vegetable flake
Courgette for blanching
Veg clip
Fine net for removing leftovers

Safe substrate: Inert aquarium gravel · Fine, smooth sand · Aquasoil for planted tanks

Work out the cost

Care routine

Daily

Check temperature and equipment
Feed
Head-count and look everyone over

Weekly

Check the air layer above the waterevery 3 days
Top up evaporationevery 3 days
Clean glass and clear algae
Test the water
Water change and gravel vacuum

Monthly

Trim and thin the plantsevery 2 weeks
Check supplies and reagent dates
Rinse the filter media

Less often

Replace chemical filter media (Carbon/Purigen)every 2 months

Vet: Quarterly review with a surface-air check — every 3 months

Top resources for more info

Independent creators and organisations we would send a friend to. We have no affiliation with any of them, and nothing here is sponsored. Links checked 2026-09-19.

YouTubers

Girl Talks FishCare how-tos by fish type, tank setup and beginner mistakes Aquarium Co-OpSpecies care guides, filtration and fish health (run by a retailer)Prime Time AquaticsSpecies profiles, stocking and water chemistry explained plainly

Sites

Seriously FishSpecies profiles with tank size, water parameters and diet for 1,800+ fish Practical FishkeepingLong-running UK fishkeeping magazine with care and species articles FishLoreCare profiles and a large keeper forum for freshwater and saltwater fish

Go deeper

Diet

Dwarf gouramis are omnivores that accept quality flakes and micro-pellets as a staple, enriched with frozen and live foods such as bloodworm, brine shrimp and daphnia, plus occasional vegetable matter.
In the wild they also pick small insects from the surface.

Feed modest amounts once or twice daily.
A varied diet supports colour and immune health, which matters given their disease susceptibility.
Avoid overfeeding, and offer a mix of floating and sinking foods to suit their mid-to-upper feeding habits.

Health

Dwarf gouramis are notably affected by Dwarf Gourami Iridovirus and a bacterial dwarf gourami disease, both common in mass-farmed stock and largely untreatable, causing wasting, sores and death.
Many fish carry these without obvious early symptoms.

The best protection is sourcing from reputable breeders, quarantining, and keeping warm, stable, clean water with low stress.
Watch for loss of colour, lesions and emaciation.
Because so much farmed stock is compromised, careful purchasing matters more here than for almost any other community fish.

Is your enclosure big enough?

Minimum volume60 litres (16 US gallons)

CompanyFine alone or with company. Best singly or as a true pair; males clash

Length

Width

Height

Units

Or tank volume

Units

Is this urgent?

In a fish tank the patient is usually the water. Test before you treat — dosing a healthy tank for a disease it does not have makes things worse.

Go now

Any detectable ammonia or nitrite in a stocked tankLarge water change now with dechlorinated, temperature-matched water. Stop feeding. Test again in 12 hours. Both are directly toxic. How toxic the ammonia reading is depends on pH and temperature, so the same number can be harmless or lethal.

Now

Fish gasping at the surface, or crowding the filter outflowIncrease surface agitation immediately, then test the water. Either the oxygen has crashed or the gills are being chemically burned. Both are hours-scale problems.

Now

Sudden deaths, more than one fish in a dayTest ammonia, nitrite, nitrate and temperature before doing anything else. Do not add medication yet. Multiple simultaneous deaths point at the water or the equipment, not at a pathogen.

Now

Today

Flashing — repeatedly scraping against decor or substrateTest the water, then look closely for parasites. Irritation is either chemical or parasitic; the test tells you which before you medicate.

Today

White salt-grain spots over the body and finsBegin the appropriate treatment today and check the temperature. The parasite's life cycle is temperature-driven, and it multiplies with every cycle you wait.

Today

Soon

Clamped fins, hiding, or refusing food for more than two daysTest the water and review recent changes. Usually the earliest visible sign of a parameter drifting.

A few days

Never add a new fish to a tank that is not fully cycled, and never treat blind. A test kit is cheaper than the fish.

This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it — and the time to find one is before you need one.

What it really costs

Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.

Region

How many animals

Your electricity price, per kWh

Buying the setup

Bedding and substrate

Substrate in an aquarium is a filter as much as a floor. Most of the biology lives in and on it.

Safe

Inert aquarium gravelRinse thoroughly before use. Grain size should be too large to swallow and too small to trap food.

safe

Fine, smooth sandCorrect for corydoras, kuhli loaches and anything that sifts. Their barbels wear away on sharp gravel.

safe

Aquasoil for planted tanksExcellent for plants, but it leaches ammonia for the first weeks. Cycle around it; do not stock into it.

safe

Bare bottomLegitimate for quarantine and grow-out tanks. Easy to clean, but it holds far less biological filtration.

safe

With a caveat

Crushed coral or aragoniteDeliberately raises hardness and pH. Correct for rift-lake cichlids, wrong for soft-water species.

with a caveat

Very deep sand bedsAnaerobic pockets form below about 5 cm in still sand. Either keep it shallow or keep it stirred.

with a caveat

Painted or coated gravelUsually fine, but coatings chip. Test a handful in a jar for a week first.

with a caveat

Never

Sharp or angular gravel with bottom-dwellersWears down barbels and leads to infection in corydoras and loaches.

never

Anything containing metal, limestone of unknown origin, or shells in a soft-water tankSlowly alters chemistry in ways that are hard to diagnose later.

never

This is our general list for freshwater fish. We have not built one specific to Gouramis yet.

My kit says 0.25 ppm. Is that dangerous?

A liquid kit measures total ammonia, but only the un-ionised fraction is really toxic, and that fraction is governed by pH and temperature — each whole pH unit multiplies it roughly tenfold. So the same reading can be nearly harmless in one tank and lethal in another; this works out which one you are in.

Total ammonia, ppm

Temperature, C