A gourami fish is a family, not an animal
The word covers about a hundred and thirty species that share one thing, and it is not a size or a temper. They breathe air at the surface, and that single fact decides the tank before any figure on a shop label does.
Wikipedia gives the scope: gouramis are a group of freshwater anabantiform fish that comprise the family Osphronemidae, and currently, about 133 species are recognised, placed in four subfamilies and about 15 genera
. The native range runs from the Indian subcontinent to Southeast Asia and northeasterly towards Korea.
On the organ that defines them: as labyrinth fishes, gouramis have a lung-like labyrinth organ that allows them to gulp air and use atmospheric oxygen, an adaptation the same source calls vital for fish that often inhabit warm, shallow, oxygen-poor water.
Aquarium Co-Op describes it in the terms a keeper meets it in, a special labyrinth organ that acts like rudimentary lungs, allowing them to gulp oxygen from the surface. Our own honey gourami record carries the same anatomy from Seriously Fish, and our betta record carries it too: a betta is not a gourami, but it is a labyrinth fish in the same suborder.
The genus names are a moving target too, and our own sources show it. Aquarium Co-Op files the dwarf gourami as Trichogaster lalius and the honey gourami as Trichogaster chuna, which is what our own record uses. Practical Fishkeeping, reporting the study in station 07, calls the same dwarf gourami Colisa lalia. Both names are for one fish: Colisa is the older genus and Trichogaster the current one, and our honey gourami record carries the same pair of names for its own species, formerly Colisa chuna.
One consequence is worth stating before the species list. Air breathing is often sold as hardiness, and it is not: Aquarium Co-Op puts a dwarf gourami in a tank with slow flow and live plants, and every source on our honey gourami record asks for the same. The organ solves oxygen. It does not solve ammonia, flow, or a tank that is too small.
What this guide is
- The question
- Six thousand seven hundred searches a month for a word that names a family of 133 species.
- Why it is filed here
- Under tank setup, because the one thing the whole family shares is a requirement about the surface of the water.
- The record behind it
- Our honey gourami record, which is the only gourami written here so far, and the one four sources call the peaceful one.
Gourami types, and the figures our sources publish for each
Three sources name species and none of them names the same set. This is every gourami our sources give a figure for, with the figure and the source beside it.
| Species | Size | What the source adds | Source |
|---|---|---|---|
| Sparkling gourami | 1.5 in, 4 cm | Kept by themselves, in pairs, or in a small group | Aquarium Co-Op |
| Honey gourami | 1.6 to 2.2 in | Single, pair, or group with similarly sized community fish. Our record asks for 4 to 6 | Aquarium Co-Op, and our own record |
| Dwarf gourami | 2 in per aqua-fish, up to 3 in per Aquarium Co-Op | One as a centerpiece fish. Almost all sold are male and they can be territorial bullies | Aquarium Co-Op, aqua-fish |
| Chocolate gourami | 2.5 in, 6 cm, per Aquarium Co-Op; 3.5 in per aqua-fish | Lots of live plants and shaded places, low pH, low GH and gentle flow | Aquarium Co-Op, aqua-fish |
| Female powder blue gourami | 3 in, 7.5 cm | Much calmer by nature, kept by herself or in a group of girls | Aquarium Co-Op |
| Pearl gourami | Up to 5 in, 13 cm, per Aquarium Co-Op; 4 in per aqua-fish | A 29-gallon tank, or a group of them in a 55 or 75-gallon aquarium | Aquarium Co-Op, aqua-fish |
| Blue or three-spot gourami | 4 in, 10 cm | no care figures | aqua-fish |
| Golden gourami | 4.5 in | no care figures | aqua-fish |
| Kissing gourami | 8 in, 20 cm | no care figures | aqua-fish |
| Giant gourami | 28 in, 71 cm | no care figures | aqua-fish |
Read the size column top to bottom and the word gourami stops being useful. A sparkling gourami is an inch and a half and a giant gourami is twenty eight inches, which is a bigger spread than any single word on this site covers. Our clown loach record is the longest fish written here at 6 to 13 inches in a tank, and it is less than half the giant gourami figure.
One source’s taxonomy is worth flagging rather than repeating. aqua-fish files most of these species in the family Belontiidae and the kissing gourami in a family it spells Heolstomatidae, while Wikipedia puts the whole group in Osphronemidae. That is the same problem our tetra fish guide ran into, where the family every care sheet names is not the family the fish are currently placed in. Nothing about keeping them changes; a reader who looks the family up finds a different answer from the one the hobby gives.
Two of the ten also have a naming problem rather than a taxonomy one: golden, blue, opaline and three-spot gourami are color forms sold under separate names, and no source we hold publishes a care difference between them. Our honey gourami record found exactly the same thing with red, sunset and gold.
The tank an air-breathing fish needs, and the three things it decides
This guide sits on the tank setup topic because the family requirement is a setup requirement. Three things follow from the labyrinth organ and our sources state all three.
- The surface has to be reachable, always. Wikipedia: the organ allows them to gulp air and use atmospheric oxygen. A fish that cannot reach the surface cannot use the adaptation that defines it, which rules out a tank with no clear water surface and rules out anything that keeps the fish pinned below.
- The flow has to be low. Aquarium Co-Op asks for slow flow for the dwarf gourami and gentle flow for the chocolate gourami. Every source on our honey gourami record describes a fish from sluggish, heavily vegetated water, and Seriously Fish calls that species slow-moving.
- Plants, and floating ones for preference. Aquarium Co-Op asks for live aquarium plants for the dwarf gourami and lots of live plants with shaded places for the chocolate gourami. Our honey gourami record carries aqua-fish asking for Anubias, java fern and Cryptocoryne plus floating Salvinia or Pistia to dim the light.
The fourth thing nobody in our sources says outright is the air above the water. An air-breathing fish in a tightly sealed tank breathes the air in the hood, so that air has to be warm and it has to be there. Our own honey gourami record asks for a lid because our sources ask for one, and the reason a gourami wants a lid is not the same as the reason a hillstream loach does: it is the temperature of the air the fish is breathing rather than the fish jumping out.
Our tank setup page collects the same requirements from every other record here, and the flow requirement is the one that puts gouramis and our siamese algae eater record in opposite tanks: that record asks for filtration rated 430 to 755 liters per hour and this family asks for as little movement as the filter can manage.
Gourami water temp and gourami pH, as a group and as a species
The group figures
- aqua-fish, for gouramis generally: a temperature of 72 to 82 °F, about 22 to 28 C, and a pH range of 5.5 to 7.5, in water it describes as soft to hard.
- Aquarium Co-Op, for the dwarf gourami: 72 to 82 °F, 22 to 28 C, pH 6 to 8, soft to hard water.
- Aquarium Co-Op, for the paradise fish, which it lists as an honorable mention: 61 to 80 °F, 16 to 27 C, and a 20 gallon or larger tank.
- Aquarium Co-Op, for the chocolate gourami: low pH and low GH, with no figures attached.
Two of those overlap almost exactly and the third does not. The two 72 to 82 bands agree; the paradise fish starts eleven degrees lower and stops two degrees earlier, which is a different fish in a different tank.
Against the one gourami written here
Our honey gourami record carries 74 to 81 °F and pH 6.0 to 7.5, both of them the span every one of its four sources contains. Put that beside the group figures and the useful point appears: the species band sits inside the group band and is narrower at both ends.
The pH is where the group figure would mislead. aqua-fish gives the family 5.5 to 7.5 and Aquarium Co-Op gives the dwarf gourami 6 to 8, so the two group figures share 6.0 to 7.5, which is exactly what our honey gourami record publishes for one species out of 133. A keeper working from the family figure has two and a half points of pH to choose from; a keeper working from a species record has one and a half.
That is the argument this site makes on every group page. Our tetra fish guide found a group pH of 6.8 to 7.8 against an ember tetra record of 5.5 to 7.0, which share two tenths of a point. A group figure is not a species figure, and on gouramis the two happen to agree better than they did on tetras.
| Published for | Temperature | pH | Hardness | Source |
|---|---|---|---|---|
| Gouramis generally | 72 to 82 °F | 5.5 to 7.5 | Soft to hard | aqua-fish |
| Dwarf gourami | 72 to 82 °F | 6 to 8 | Soft to hard | Aquarium Co-Op |
| Paradise fish | 61 to 80 °F | not stated | not stated | Aquarium Co-Op |
| Chocolate gourami | not stated | Low, no figure | Low GH, no figure | Aquarium Co-Op |
| Honey gourami | 74 to 81 °F | 6.0 to 7.5 | 71 to 214 ppm | Our record, from four sources |
| Dwarf gourami, to breed | 80 to 82 °F | not stated | not stated | Aquarium Co-Op |
Are gourami schooling fish? No, and the numbers are per species
Nothing in our sources describes a gourami as a schooling fish, and the group advice they do give is species by species rather than family wide.
- Dwarf gourami: Aquarium Co-Op keeps one as a centerpiece fish, and says why: almost all of the dwarf gouramis you see at the pet store are male and they can be territorial bullies. Multiple males produce squabbling, chasing, fin nipping, and other damage.
- Female powder blue gourami: by herself or in a group of girls, per the same source, which calls her much calmer by nature.
- Sparkling gourami: by themselves, in pairs, or in a small group.
- Honey gourami: single, pair, or group with similarly sized community fish per Aquarium Co-Op, while Seriously Fish asks for no less than 4 to 6 specimens on our own record.
- Pearl gourami: a 29-gallon tank for one, or a group of them in a 55 or 75-gallon aquarium.
Read that list and the family splits into two kinds of fish: the ones our sources will keep alone and the ones they will keep in numbers. The line runs through the sexes rather than through the species, and the dwarf gourami is the clearest case: the same source that will not keep two males will keep a group of females.
How many gouramis in a 10 gallon tank
One, on the figures our sources publish. Aquarium Co-Op’s minimum for a dwarf gourami is a 10-gallon or larger aquarium with slow flow and live plants, and it keeps that fish singly. Our honey gourami record prints 10 gallons as the smallest figure any source states for a pair or small group, with Aquarium Co-Op asking for 20 for three. Nothing our sources publish puts more than a pair of any gourami in ten gallons, and the pearl gourami figure of 29 gallons for a single fish is the reminder that the answer depends entirely on which species is in the bag.
Gourami male vs female, and what to look at on the body
Two sources give a method and both are about fins rather than about the body or the color. Aquarium Co-Op, on the dwarf gourami: males are usually more colorful and have a dorsal fin with a pointy end, whereas females have a dorsal fin that is more rounded. Our honey gourami record carries Wikipedia saying the male has longer fins, with a pointed dorsal fin and extended anal fin rays, and Seriously Fish saying adult females are normally fuller-bodied and larger than comparably-aged males.
The catch is on our own record and it applies to the whole family: Seriously Fish records that the nuptial color change does not occur in males of the various ornamental strains, and the ornamental strains are what shops stock.
Gourami tank mates, and do gouramis eat shrimp?
The tank mate question has the largest search volume of anything in this cluster after the family name itself, and our sources answer it for two species out of 133.
What Aquarium Co-Op names
For the dwarf gourami: corydoras catfish, tetras, rasboras, loaches, and platies. Four of those five are records here, our corydoras, ember tetra, chili rasbora and two loaches, and the loach half needs the temperature checked: our kuhli loach record stops at 79 °F and our clown loach record prints 82.
Do gouramis eat shrimp? One source says yes, by accident
Aquarium Co-Op, on the dwarf gourami: they will opportunistically snack on anything that can fit in their mouths, like cherry shrimp and baby fish.
That is the only direct answer in our sources and it is worth reading precisely. It is not a predator warning, it is a mouth-size warning, and it is the same rule our clown loach record carries from the same publisher. Our cherry shrimp record carries a 30 to 40 mm adult whose young hatch at about a millimeter, so the adults are outside a dwarf gourami mouth and the colony is not.
Nothing our sources publish says the same about the honey gourami, whose own record carries three sources calling it peaceful. A three inch gourami and a two inch gourami are not the same tank mate, which is the whole argument of this guide in one sentence.
Gourami and betta, gourami with guppies
Both pairings are searched and neither is settled by anything we hold. On the betta: our betta record carries one source that will not put a betta in a community tank at all against another naming five tank mates, so our tank mates grid marks betta with honey gourami a caution and prints the reason. Both are labyrinth fish, both build bubble nests, and both are sold to the same beginner.
On guppies, no source on either record names the pairing. What the records hold is arithmetic: our guppy record carries 63 to 82 °F and our honey gourami record 74 to 81, so the water allows it with room to spare, and the mouth-size rule above is the only warning either record supports. A guppy is 2 to 2.5 inches, which is bigger than a dwarf gourami mouth and smaller than a pearl gourami.
Dwarf gourami disease, and a shop that has never seen it
What the research says
Practical Fishkeeping, reporting a study on iridovirus in dwarf gouramis and Murray cod, publishes the figure this whole subject rests on: around 22 percent of dwarf gouramies in Australian aquarium retail stores were infected.
The rest of the report is about where the virus traveled. Murray cod iridovirus and dwarf gourami iridovirus were 99.95 percent identical over 4527 base pairs, and all three viruses in the comparison, including infectious spleen and kidney necrosis virus, shared 99.9 percent similarity. All the gouramis examined were imported from suppliers in Singapore, and the same source notes that UK dwarf gouramis come from the same region.
The conclusion it quotes is about trade rather than about tanks: the global trade in ornamental fish may facilitate the spread of Megalocytivirus and enable emergence of disease in new host species in distant biogeographic regions. The Murray cod outbreak it links to was on a fish farm in 2003.
Practical Fishkeeping gives no advice to fishkeepers at all, which is worth saying because every page that cites this study seems to.
What the shop says
Aquarium Co-Op sells these fish and its care guide takes the opposite position from its own experience: after years of buying thousands of dwarf gouramis for our fish store, we have yet to personally encounter this disease.
It does report a different problem in the same breath, occasional batches that have genetic deformities caused by overbreeding.
What this guide does with that
We print both and take neither, and here the two are not even measuring the same thing. A study testing fish in Australian shops with a molecular assay and a retailer describing what it has seen in its own tanks can both be accurate: a virus detected in a fifth of shop fish is not the same claim as a fifth of shop fish visibly dying of it, and neither source says how often infection becomes disease.
What follows for a buyer is smaller than either headline. The dwarf gourami is the one gourami in this family with a documented trade-borne virus attached to its name, and the one our sources most often describe as a territorial bully. Aquarium Co-Op’s own list of five peaceful gouramis does not include it, and the fish it puts first on that list is the honey gourami, which is the species written here.
Our water and health page is where this site keeps disease claims, and its rule applies here: no dose, no treatment protocol, and no diagnosis from a description.
Gourami breeding, bubble nests and mouths
What the family does
Wikipedia gives the behavior for the whole group and it is not one behavior: all living species show parental care until fry are free swimming: some are mouthbrooders and others build bubble nests.
That single sentence is the most useful thing on this page for anybody who finds eggs. A gourami holding eggs in its mouth and a gourami guarding a raft of bubbles are both doing the normal thing for their species, and no source we hold lists which of the 133 species does which.
For the two species our sources cover, both are bubble nesters. Aquarium Co-Op calls the dwarf gourami relatively easy to reproduce via bubble nesting, and asks for a 10-gallon tank, shallow water between 6 and 8 inches deep, and 80 to 82 °F.
Our honey gourami record carries the timetable for the other one: eggs hatch in around 24 to 36 hours per Seriously Fish and Aquarium Co-Op, approximately two days per Wikipedia, and the fry become free swimming in another 24 to 48 hours, needing infusoria or liquid fry food for the first week before they can take brine shrimp nauplii.
The dispute our own record carries about the nest
It is worth repeating here because it is checkable and because it is about the structure this family is known for. Seriously Fish, on the honey gourami: unlike those of some related species the bubblenest does not include pieces of plant material. Wikipedia, on the same fish: males construct floating nests composed of air bubbles, often incorporating plant material.
Our honey gourami record prints both and settles neither. If your pair spawns, the nest itself is the evidence, which makes it the rare disagreement on this site a keeper can resolve by looking.
Why breeding is a species question and not a family one
Read the two temperatures together and the reason appears. To breed a dwarf gourami Aquarium Co-Op asks for 80 to 82 °F, which is above the ceiling our honey gourami record publishes for keeping that species at all, 74 to 81. Two fish in the same family, one breeding figure above the other’s keeping range.
Our breeding page collects the same pattern from the other records here, and our brine shrimp guide exists because of the fry instruction above: the first week of a gourami fry’s life needs food smaller than anything sold in a shop.
What do gouramis eat, and how long do gourami fish live?
The diet
Aquarium Co-Op, on the dwarf gourami, gives the fullest list any of our sources publishes: a varied, omnivorous diet of fish flakes, floating betta pellets, community pellets, bloodworms, daphnia, brine shrimp, and algae.
Our honey gourami record carries the same shape from four sources: an insect eater in the wild that takes almost anything in a tank, with Seriously Fish asking for small live or frozen Daphnia, Artemia or bloodworm regularly and aqua-fish adding spirulina flakes or blanched spinach and peas.
Two details are worth keeping. Floating pellets suit a fish that feeds at the surface, which is where a labyrinth fish already spends its time. And Seriously Fish’s warning on our own record applies to the whole family: a slow fish is easily out-competed for food by more vigorous tankmates, which makes the tank mate list in station 06 a feeding decision as much as a temperament one.
The lifespan
Two figures, and they are not the same kind of figure.
- Wikipedia, for the family: gouramis can live for 1 to 5 years.
- Aquarium Co-Op, for the dwarf gourami: about 2 to 4 years with proper care.
- Our honey gourami record: 2 to 5 years, from aqua-fish, and it is the only one of that record’s four sources to publish a lifespan at all.
All three overlap from 2 to 4 years, which is short for a fish this size. Our guppy record carries 2 to 3 years and our ember tetra record 2 to 4, so a gourami is in the same bracket as the small livebearers and tetras rather than the decade-long fish.
The family figure has a floor nobody explains. One year, per Wikipedia, is lower than any fish record on this site publishes, and no source we hold says which of the 133 species it belongs to.
What this guide will not answer
Care figures for 127 of the species
Our sources publish a size for ten gouramis and care figures for six. Wikipedia counts about 133 species. Anything past station 02 is a species question, and this site answers those with records rather than with a family page.
Whether your dwarf gourami has the virus
A study found around 22 percent of shop fish infected in one country and the largest retailer we cite has never seen the disease. Neither source turns into a diagnosis, and this guide will not print one.
Gourami breeding, beyond the family behavior
Wikipedia: all living species show parental care until fry are free swimming, some are mouthbrooders and others build bubble nests. Which of those a given species does is a species question, and our honey gourami record is the only one answered here.
Whether the color forms differ
Gold, blue, opaline and three-spot are sold as separate fish and no source we hold publishes a care difference between them. Our honey gourami record found the same with red, sunset and gold.
A group tank size
Nobody publishes one for the family, and the species figures run from 10 gallons for a dwarf gourami to 29 for a single pearl gourami. A family figure here would be an average of two answers that do not belong to the same fish.
Gourami behavior beyond the aggression note
Aquarium Co-Op says dwarf gourami aggression is highly variable by individual: some are pretty mellow, some aggressive only during mealtimes, and some indiscriminately attack any creatures that cross into their territory. That is a description of variance, not a prediction, and no source we hold improves on it.
Gourami questions, answered from the sources
What is a gourami fish?
A member of the family Osphronemidae, which Wikipedia puts at about 133 species in four subfamilies and about 15 genera, native from the Indian subcontinent to Southeast Asia and northeasterly towards Korea. What the family shares is the labyrinth organ: a lung-like organ that allows them to gulp air and use atmospheric oxygen.
What are the types of gourami?
Our sources give a size for ten: sparkling at 1.5 in, honey at 1.6 to 2.2, dwarf at 2 to 3, chocolate at 2.5 to 3.5, female powder blue at 3, pearl at 4 to 5, blue or three-spot at 4, golden at 4.5, kissing at 8 and giant at 28 inches. Aquarium Co-Op’s five peaceful picks are the female powder blue, pearl, chocolate, sparkling and honey gourami, with the paradise fish as an honorable mention.
What is the right gourami water temp?
72 to 82 °F is the group figure, published by aqua-fish for gouramis generally and by Aquarium Co-Op for the dwarf gourami. The exception among our sources is the paradise fish at 61 to 80 °F. Our honey gourami record narrows it to 74 to 81 for that species, which is the span all four of its sources contain.
What gourami pH should the tank be?
The two group figures share 6.0 to 7.5. aqua-fish gives the family 5.5 to 7.5 and Aquarium Co-Op gives the dwarf gourami 6 to 8. Our honey gourami record publishes 6.0 to 7.5 for one species, which is the same window the two group figures overlap on. The chocolate gourami is the outlier: Aquarium Co-Op asks for low pH and low GH without figures.
Are gourami schooling fish?
No source we hold calls them schooling. The group advice is per species and often per sex: Aquarium Co-Op keeps a single dwarf gourami as a centerpiece because almost all sold are male and they can be territorial bullies, keeps female powder blue gouramis in a group of girls, and keeps sparkling gouramis alone, in pairs or in a small group, which is the low end of the range on our own sparkling gourami record, where two other sources ask for four or more and one for five or six. Seriously Fish asks for 4 to 6 honey gouramis on our own record.
How many gouramis in a 10 gallon tank?
One, or a pair of the smallest species. Aquarium Co-Op’s dwarf gourami minimum is a 10-gallon with slow flow and live plants, kept singly. Our honey gourami record prints 10 gallons as the smallest published figure for a pair or small group and notes that the same publisher asks for 20 gallons for three. A single pearl gourami needs 29 by the same source.
What are good gourami tank mates?
Aquarium Co-Op names corydoras catfish, tetras, rasboras, loaches and platies for the dwarf gourami. Four of those are records here, and the loach half needs the water checked: our kuhli loach record stops at 79 °F and our clown loach record prints 82. The warning that matters more comes from our honey gourami record, where Seriously Fish says a slow-moving gourami is easily intimidated or out-competed for food by larger or more vigorous tankmates.
Do gouramis eat shrimp?
One source answers directly. Aquarium Co-Op, on the dwarf gourami: they will opportunistically snack on anything that can fit in their mouths, like cherry shrimp and baby fish. It is a mouth-size rule rather than a predator warning, and nothing our sources publish says the same about the honey gourami.
What do gouramis eat?
A varied omnivorous diet. Aquarium Co-Op names fish flakes, floating betta pellets, community pellets, bloodworms, daphnia, brine shrimp and algae for the dwarf gourami. Our honey gourami record carries an insect eater in the wild that takes almost anything in a tank, with small live or frozen Daphnia, Artemia or bloodworm asked for regularly and spirulina flakes or blanched spinach and peas added by one source. Floating food suits a fish that already spends its time at the surface.
How long do gourami fish live?
Two to four years is where our three figures overlap. Wikipedia gives the family 1 to 5 years, Aquarium Co-Op gives the dwarf gourami about 2 to 4 with proper care, and our honey gourami record carries 2 to 5 from the only one of its four sources to publish a lifespan. Nobody says which species the one-year floor belongs to.
What is dwarf gourami disease?
Iridovirus, and our two sources disagree about how much it matters. Practical Fishkeeping, reporting a study, says around 22 percent of dwarf gouramis in Australian aquarium retail stores were infected, that dwarf gourami iridovirus and Murray cod iridovirus were 99.95 percent identical over 4527 base pairs, and that all the gouramis examined were imported from suppliers in Singapore. Aquarium Co-Op says that after years of buying thousands of dwarf gouramis for its store it has yet to personally encounter this disease. A virus detected by assay and a disease seen in a tank are not the same measurement, and neither source says how often one becomes the other.
Which gourami is best for a gourami community tank?
On our sources, the honey gourami. A gourami community tank works on temperament rather than on the family name, and the family covers everything from a peaceful two inch fish to a twenty eight inch one. Aquarium Co-Op titles its care guide for it “our favorite peaceful gourami” and puts it on a list of five peaceful gouramis that does not include the dwarf gourami. Three of the four sources on our own honey gourami record call the species peaceful, and the fourth calls it relatively timid, which is the condition rather than a contradiction: a peaceful fish in a tank of fast eaters is a hungry one.
Can a gourami live with a betta?
Our records mark it a caution rather than a refusal, and the reason is on the betta record rather than on the gourami. That record carries one source that will not keep a betta in a community tank at all against another that names five tank mates. The water is not the problem: 72 to 86 °F there against 74 to 81 on our honey gourami record. Both fish are labyrinth breathers that build bubble nests.
How do you tell a male gourami from a female?
By the dorsal fin, per two sources. Aquarium Co-Op on the dwarf gourami: males are usually more colorful with a dorsal fin that has a pointy end, while females have a more rounded one. Wikipedia on the honey gourami: the male has longer fins with a pointed dorsal fin and extended anal fin rays. Seriously Fish adds that females are normally fuller-bodied and larger, and warns that the nuptial color change does not occur in males of the ornamental strains most shops sell.