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Related FAQs: Rainbowfishes 1, Rainbowfishes 2, & FAQs on: Rainbow Identification, Rainbow Behavior, Rainbow Compatibility, Rainbow Selection, Rainbow Systems, Rainbow Feeding, Rainbow Disease, Rainbow Reproduction,

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Back to Survey Articles on: Freshwater Fishes, Atheriniform Fishes, 

Rainbowfishes... Melanotaeniids and More

by Bob Fenner

Telmatherina bonti

The order of  "Silverside" fishes Atheriniformes contains a mix of fishes spanning two suborders and three-four families that are commonly called Rainbowfishes (though some folks would leave out, gladly, the Betodiidae of Madagascar... the Blue Eyes...) Though a handful of these species have been employed as ornamentals for the last few decades, only until the nineties did many new forms make their "splash"... becoming the "Gouramis" of their time (and now!) in terms of popularity. This status is well-deserved. These fishes are lively, beautiful (well, most of them, as adults, in good health...), hardy, and actually enjoy the all-too-typical hard and alkaline water that many folks are faced with as mains/tap supply. 


Hmm, let's see, most atheriniforms have two separate dorsal fins. Their lateral lines are either absent completely or very weak in appearance. Some other arcane internal features could be mentioned (see Nelson). Let's mention the peculiarity of their larval gut lengths... they're short. Some indication of their need for continuous feeding, and slow rates of growth as/when young.  Eight families comprising forty seven genera, 285 or so species. Some of all three suborders of the Order Atheriniformes, four families and more than a hundred species bear the common moniker "Rainbowfish"... though to science, the Family Melanotaeniidae are THE Rainbows. 

The Pet-fish named Rainbowfishes: Commonly encountered species

Order Atheriniformes

    Suborder Bedotioidei

        Family Bedotiidae: The Madagascar "Rainbowfishes". All freshwater. two genera, about nine species.

Bedotia geayi Pellegrin 1907, the Red-Tailed Silverside. One of the more popular "Rainbowfishes" from eastern Madagascar. Conditions: pH 7-8, dH 9-19, temp. 20-24C.

Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

    Suborder Melanotaenoidei

        Family Melanotaeniidae: The true Rainbowfishes. Mostly freshwater, some brackish. Tropical and subtropical Australia, New Guinea. Six genera, about eighty-five species.      

            Genus Chilatherina: Nine species.

Chilatherina bleheri Allen 1985, Bleher's Rainbowfish. Irian Jaya, Indonesia. To nearly five inches in length. Cond.s: pH 7, dH 8-15, temp. 23-27. 

            Genus Glossolepis: Seven species.

Glossolepis incisus Weber 1907, the Red Rainbowfish. Lake Sentani, Irian Jaya, Indonesia. Males to nearly five inches, females to four. Cond.s: pH 7-8, dH 9-19, temp. 22-24 C. A standard offering in the pet-fish interest. Young and older males.

Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Glossolepis wanamensis Allen & Kailola 1979, the Lake Wanam Rainbowfish. Papua New Guinea. Cond.s: pH 7.8, dH 10, temp. 26-30. Aquarium pair. Gary.L input: "The photo of the G. wanamensis is listed as an "aquarium pair". This would not be the case at all as the fish in front of the male wanamensis is some sort of a Melanotaenia. It may be a non-cross it's just too tough from the picture to definitely label it. The strong lateral line marking obviously makes it something other than a G. wanamensis though."

           Genus Iriatherina: One species.

Iriatherina werneri Meinken 1974, the Threadfin Rainbowfish. Central-southern New Guinea and northern Australia. In the wild feeds on diatoms and small crustaceans. Males 1 1/2, females 1 1/4" in length. Cond.s: pH 6-8, dH 5-12, temp. 26-30 C. 

            Genus Melanotaenia: Forty two species, four subspecies recognized. 

Melanotaenia boesemani Allen & Cross 1980, Boeseman's Rainbowfish. Vogelkop Peninsula, Irian Jaya, Indonesia. Males 9 cm, females 7 cm. Cond.s: pH 7-8, dH 9-19, temp. 27-30 C. Aquarium males interacting. 

Verticals (Full/Cover Page Sizes Available
Melanotaenia herbertaxelrodi (Allen 1981), the Lake Tebera Rainbowfish. Lake Tebera Basin, southern highlands, Papua New Guinea. Males to three and three quarters, females to three inches in length. Aquarium image of young males and a female and male. Cond.s: pH 7.5-7.8, dH to 10, temp. 20-26 C. Needs harder, alkaline water. 

Bigger PIX: The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Melanotaenia lacustris Munro 1964, the Lake Kutubu or Blue Rainbowfish. Southern highlands Papua New Guinea. To four inches in length. Freshwater. Cond.s: pH 7-8, dH 9-12, temp. 20-24 C. Males in captivity. 

Melanotaenia praecox (Weber & Beaufort 1922), the Dwarf Rainbowfish. Mamberamo River, northern Irian Jaya, Indonesia. To two inches in length. Both females and males develop color of shiny blue. Males with red margins on their fins.

Melanotaenia splendida australis Castelnau 1875, the Western Rainbowfish. Northwestern Australia. Males to four inches, females about an inch shorter. Freshwater. Cond.s: pH 6.5-8, temp. 22-28 C. A group of males in captivity. 

Melanotaenia trifasciata (Rendahl 1922), the Banded Rainbowfish. Northern Australia, Queensland. Males to four inches, females about an inch shorter. Freshwater. Cond.s: pH 7-8, dH 9-19, temp. 25-30 C. A large male in captivity. Many color variants exist in this wide-ranging species.  id correction:  "I also have some problems with your other pictures. The "trifasciata" is not a trifasciata at all but rather the infamous cross "Crossing Rainbow". It goes by a few other names such as the "royal rainbow" and a few others. I thought we had a "hall of shame" on the rainbowfishes.org site"

Verticals (Full/Cover Page Sizes Available

            Family Pseudomugilidae: The Blue Eyes: Brackish and freshwater. New Guinea, Australia, Indonesia. Three genera (Kiunga, Pseudomugil, Scaturiginichthys), about fifteen species. 

Pseudomugil furcatus (signifer image according to another source) (Nichols 1955), the Forktail Rainbowfish. Lowlands of eastern Papua New Guinea. Males to two inches, females slightly smaller. Cond.s: pH 6-8, dH 5-12, temp. 24-26 C. 

Pseudomugil signifer Kner 1866, Pacific Blue Eye. Australian endemic; found in fast running streams into brackish mangroves. To two inches in length. Aquarium pix. 

Looks like some sort of Atherine, perhaps a Pseudomugil. Interzoo 2010

    Suborder Atherinoidei: Five families. Many important foodfishes... Grunion... 

        Family Telmatherinidae: The Sailfin Silversides or Celebes Rainbowfishes. Fresh, brackish, marine. Sulawesi and New Guinea. Five genera, seventeen species.

Marosatherina (formerly Telmatherina) ladigesi (Ahl 1936), the Celebes Rainbowfish. South Sulawesi, Indonesia. To about three inches in length. Cond.s: pH 7-8, dH 9-19, temp. 23-28 C. The only commonly offered member of the family.


Telmatherina bonti Weber & de Beaufort 1922. Sulawesi, Indonesia. To 6.5 cm standard length. Aquarium photo. 


About Brackish Rainbows:

    Most notably the Celebes (Marosatherina (Telmatherina) ladigesi), Madagascar (Bedotia geayi), Red New Guinea (Glossolepis incisus) and  many of the Rainbows of the genus Melanotaenia (e.g. the Queensland, M. maccullochi and Australian, M. fluviatilis) do much better with a modicum of salt (spg of 1.005) in their water, though they can live in straight freshwater. 



   Collection of your own specimens is a life long dream of many "Bow" aficionados. I have a few friends who have made sojourns to New Guinea and Australia in pursuit of the ultimate experience. To live where their favorite fishes come from. This is assuredly hard work, let me assure you. 

    Most folks settle for buying captive-produced stocks out of the Far East (mainly Hong Kong and Singapore), though there are excellent sources in Germany, elsewhere in Western Europe and many breeders in the United States. You can find these commercial interests on the Internet, through national hobby magazines, and they and other hobbyist suppliers through a few clubs, bulletins and "user-groups" on the Web (see biblio. below). There are a few to several species that are so popular that larger, better-stocked retail livestock fish stores carry them as well. 

Excerpted from: Forgotten Fish; Old-timers with plenty to offer by Neale Monks   

Reliable rainbowfish 

Fast-forwarding a few decades, and among the new kids on the block during the 1980s were various species Australian rainbowfish. Rainbows, of course, remain popular fish, but the focus has shifted way from the Australian species towards the rather more colorful ones from Papua New Guinea. Nonetheless, you will see Australian rainbowfish up for sale periodically, and while they don't look much when young, once they mature, they can be very nice fish indeed. This is actually a problem with rainbowfish generally: very few of them are colorful when immature, and especially not when crowded into a retailer's tank. So with rainbows you really do need to take it on trust that the ugly ducklings in the tropical fish store will actually turn into those brilliant fish you see in your books and magazines! Once they do mature, rainbows can be relied on to remain in good health for many years, with the larger species typically living for at least five years. 

A typical example is Melanotaenia maccullochi, sometimes known as the Queensland rainbowfish. Bluish at the front and reddish at the rear, the two colors merge into one another mid-flank as a series of horizontal bands. At under 3" in length, these are very accommodating and manageable fish that work well in practically any community, but as with rainbowfish generally, their high level of activity does mean they need plenty of swimming space. The Queensland rainbow was one of the first Australian freshwater fish to be traded in the aquarium hobby, way back in the 1930s, though it didn't become widely sold for some decades after that. 

Another early export from the Antipodes was the Cape York rainbowfish Melanotaenia splendida. This is a fairly large rainbowfish that reaches a length of about 6" and has a steely-blue body marked with a few horizontal red stripes. It isn't so much its colors that make it attractive as its patterning, which is complex and covers not just the flanks but also the fins with fine red and blue spots and stripes. Like many other rainbows, mature males have a very hump-backed appearance that makes them very impressive animals and easy to distinguish from the females. Males spend a lot of their time displaying to rivals, holding out their fins and sizing one another up. Presumably, this is meant to impress the females, but in aquaria it makes these fish a bit more entertaining than the average schooling barb or tetra. Cape York rainbows are hardy and adaptable, and were among the first rainbows to become established in the hobby, first appearing in the US during the early 1970s. While not very widely seen anymore, it is an excellent choice for community tanks containing moderately large but peaceful species.



    System size is important. "Bigger is better" of course, with the smaller species being able to be kept in small numbers in twenty gallon plus aquariums. Larger species of real Rainbows in groups call for forty gallon plus volumes; the largest species need a hundred gallons and more to look, be their best in a school. 

    Live plants should be a given when considering, stocking these fishes. For all the many benefits they are, food, cover, oxygen generators, waste consumers, do have live plants with your Rainbows.  Simple types like Vallisnerias, Sagittarias, Ceratopteris (Water Sprites) will do, though there are many, many other choices. For casual breeders who don't want to utilize yarn "mops" to collect eggs, Java Moss (Vesicularia), Hornwort/Coontail (Ceratophyllum), Foxtail/Milfoil (Myriophyllum) can be considered. I strongly suggest the addition/mixing of a clay-type soil in the lower level/s of your substrate to boost plant growth. 

    Lighting to suit the plants in intensity, quality and duration is fine for these fishes as well. Some sunlight being allowed to reach the tank, even indirectly is encouraged. You may not believe it (till experience changes your mind), but these fishes do actually bask (sunbathe if you must) in sunlight.


    As a group, the true and not-so Rainbowfishes are very adaptable, coping in a wide range of water qualities. For most species temperature, hardness and pH of 24-26 C. (75-79 F.), dH of 6-10 and neutral pH (near 7) are ideal, but values about these numbers are fine (though species of Iriatherina and Rhadioncentrus prefer pH's in the 5.5-6.8 area... and some Pseudomugils do better at elevated temperatures.), and more important is stability all the way around. The vast majority of tap-waters are fine used as is (dechlorinated/dechloraminated of course) for regular (weekly) partial (10-20%) water changes. The immediate increased activity and color of specimens concurrent with this maintenance are appreciable. 

    A note to those who feel or have an actual need to modify their Rainbowfishes water chemistry. If you're adding salt, changing pH or hardness overtly, do so in advance of using such water in a separate storage container. This stored, pre-made new water is best kept in a designated container, near the main/display system with its own pump (to circulate, transfer the water) and heater. These are far from "touchy" fish species, but this simple arrangement and practice does a myriad of "goods".

Gary.L input: "Water changes. Rainbowfish REALLY like water changes. I typically perform 50% water changes on my fish (weekly suggested but at least 1x every 2 weeks) and they really enjoy this. 10-20% weekly changes really just doesn't get the job done. Hardness, pH On the GH side anywhere between 100 ppm - 250 is fine for them. Harder is ok too but they get tougher to breed and the eggs sometimes don't hatch at the higher hardness values. On the KH end I feel that it is extremely important to get at least 3-4 degrees of carbonate hardness here. If you have softer water supplement it by adding baking soda, sodium bicarbonate. In my water a tablespoon in ~ 55 gallons increases by about 1 degree KH. pH bounce is something that really stresses rainbowfish and if present can cause them to get TB. Most of the rainbowfish people have pretty well discounted the other wasting diseases. TB is not easy to test for but when it has been done - skin ulcers, mouth ulcers, bloating (shot kidneys) and wasting have all been positive for TB."



    To a one, these fishes can be considered "community" species (though some quite large at adult size), getting along with others of their kind and other fish life. If their accompanying tankmates can stand the Rainbows rapid, continuous swimming behavior there is a good chance they'll all get along fine. 

    Male-male displays, particularly in situations where there are disproportionate numbers of males to few females, may become heated at times, but rarely result in real injury. The general rules of careful observation of your livestock, under-crowding, providing plenty of cover for sub-dominant individuals applies here to prevent damage, losses. 

    These are schooling species. They live in groups that may total only a handful of individuals to dozens. They will only do and show their best maintained in numbers in large enough systems to allow their shoaling behavior. Good-sized volume of system and presence of their kind will virtually eliminate any ill-effects of aggression amongst them. About equal sex-ratios work well in most settings. 


    Given healthy specimens, and pre-set water conditions, a cycled system with live plants, acclimating these fishes is a breeze. Some ready mixing of water from the main system, either through a drip approach or periodic ladling, will do to ready them for placement. 


    Breeding these fishes is a fun/trying, easy/hard enterprise. Fun and easy because so many species do readily spawn in a wide range of conditions; trying and hard for the one-at-a-time egg-laying/fertilization process and seemingly slow progress of growth of their young. The sexes are easily told apart as they mature by the males larger size, more flowing unpaired fins and better coloration. 

    You will know by their intense coloration, rapid swimming, forays into plant thickets, fin extension that your Rainbows are breeding. The small (1-2 mm) eggs are hard to make out (use a bright, focused flashlight), hatch out in 5-12 days (depending on species, temperature), and may be consumed by their parents (commercial breeders remove the spawning medium or parents).  Small live foods like rotifers and brine shrimp nauplii, microworms are of use as first foods and lesser so, dried prepared foods of small size. 

    Commercial, large-scale production methods vary... some folks separating males, females for conditioning... others leaving out spawning media in the breeders bare tanks when they don't want them breeding. There are folks who utilize ponds, large tanks and move spawning materials with eggs on a semi-continuous basis to optimize yields. Some friends of mine in the industry use nothing in their water to prevent fungusing of eggs, other writers swear by the addition of methylene blue, acriflavine for this purpose. If you are interested into delving into these controversies, peruse the literature cited below (there is much more).  

About Crosses: Please don't do or Sponsor this!

Here's a cross between Glossolepis incisis and Melanotaenia boesemani... A very common possibility between species of Melanotaenia, Chilatherina, Glossolepis... to be avoided IMO. Crosses even across genera do occur, some are even commercially produced. Regrettable. Gary.L input: "one of these same crosses. Whether it's incisus x boesemani or incisus x herbertaxelrodi I guess is still an unknown"


    All of these fishes readily accept all forms of foods, live, dry, freeze-dried, frozen/defrosted that are small enough to be taken in their small mouths. Do study their natural food choice/habits (e.g on fishbase.org) and try to provide them with some live foods everyday. Mosquito, Glassworm (Chironomid) larvae, brine shrimp, Daphnia, wingless fruit flies, small worms, even ants are consumed greedily by most species. Take care to provide foods in small quantities over an extended period of time (minutes) for these fishes, as most are "surface" feeders. 

    Some authors cite once daily feedings as being adequate. I prefer two, three small feedings for color, growth and encouraging foraging behavior. 

    Hunter (1997) emphasizes the use of greenery in these fishes diets. He states that supplying zucchini (without the rind) as an adjunct to ensuring good spawning success. 

Disease Prevention/Cure

    Though not widely regarded as a disease per se, senescence and death by "old age" is a factor of interest in husbandry of all life. Small species in these families can be expected to live 2-3 years, larger ones perhaps 4-8 years in captivity. You may well want to acquire your specimens at sub-adult sizes/ages to assure having and breeding them a good long while. 

    These fishes can contract and succumb to parasitic diseases, though they are amongst the last fish groups to do so in terms of order or susceptibility. Happily, correcting the root causes of such infestations, treatment with standard approaches is efficacious. 

    There is an "environmental" infectious (bacterial) condition/disease that at times has reached pandemic proportions. This "Rainbowfish Disease" shows as a rapid onset degeneration of body scales, flesh. Hammer (1996) writes of his successful trials with the antibiotic Ceftin (Cefuroxime axetil). Quarantine (two weeks), care in selecting healthy specimens, providing optimized and stable appropriate habitats and feeding will likely spare you from exposure to this complaint.


    So it goes for this brief expose of these closely-related families. Bored with a general community aquarium mix? Not up to the hectic scramblings of  African Cichlids? No desire for a big, ugly eat-em-up specimen tank? Not ready, desirous of delving into marines, but want fishes just as beautiful? Do consider the Rainbowfishes, real and not. They're hardy as freshwater fishes come, interesting to a fault, fun, even possibly profitable to breed and raise, and gorgeous and interesting in body shape, finnage and color. 

Thanks to:

    Friends Kent Webster and Jorge Sanchez (Sahul Aquatics) of California for help in identifying my photographs of these fishes,  general input and camaraderie. 


Bibliography/Further Reading:

Gary Lange: How to make spawning mops: http://rainbowfish-forum.freeforums.net/thread/51/mop-breeding-rainbowfish



Australian, New Guinea fishes association and affiliates: http://www.angfa.org.au/angfa.htm, http://www.angfa.org.au/groups.htm


Allen, Gerald R. 1978. The Rainbowfishes of Northwestern Austrailia. TFH 6/78.

Allen, Gerald R. 1981. Central highlands Rainbows from Papua New Guinea, with descriptions of two new species (Melanotaeniidae). TFH 1/81.

Allen, Gerald R. & Norbert J. Cross. 1982. Rainbowfishes of Australia and Papua New Guinea. T.F.H. Publications, NJ. 141pp. 

Bleher, Heiko. 1984. Mysterious Rainbowfish, pts 1,2. TFH 3,5/84.

Castro, Alfred D. 1995. They're Rainbows. Not always easy to find, but well worth the effort. pts 1,2  AFM 6,7/95.

Hammer, Harvey M. 1996. Rainbowfish- disease and treatment. FAMA 6/96.

Hunter, Roy. 1997. Rainbowfish (sic), from nature to your aquarium. AFM 6/97.

Hunziker, Ray. 1992. Keeping and breeding Rainbowfishes. TFH 10/92.

Jackson, Andy. 1987. Rainbows: the next big thing? FAMA 12/87.

Kirtley. Paul T. 1986. Spawning Rainbowfishes made simple. TFH 10/86.

Nelson, Joseph S. 1994. Fishes of the World. John Wiley & Sons, NY. 600pp.

Reed, Mike. 1999. They call them "Bows". TFH 5/99.

Tappin, Adrian R. 1993. The Rainbow revolution. FAMA 5/93.

Taylor, Edward C. 1982. In search of Rainbows, pts 1-4. TFH 3,4,7,10/82.

Taylor, Edward C. 1999. Over the Rainbows. Pet Business 1/99.


Palicka, Jiri. 2000. Species profile: Bedotia geayi. TFH 2/2000.

Siegl, W. 1960. A new fish for all- Bedotia geayi. TFH 6/60.

Taylor, Edward C. 1982. The Madagascar Rainbow Bedotia geayi. FAMA 6/82. 

Van Camp, Sally. 1987. Spawning Bedotia geayi, an unconventional way. FAMA 4/87. 


Allen, Gerald R. 1980. Chilatherina axelrodi, a new species of Rainbowfish (Melanotaeniidae) from Papua New Guinea. TFH 1/80.

Allen, Gerald R. 1984. Boeseman's Rainbowfish- the pearl of Irian Jaya. TFH 2/84.

Armstrong, Neil. 1983. Spawning Melanotaenia herbertaxelrodi, the Lake Tebera Rainbowfish. TFH 3/83.

Franco, Phillip S. 1969. Breeding the Rainbowfish (M. mccullochi). The Aquarium 7/69.

Glass, Spencer. 1997. The Dwarf Neon Rainbowfish. TFH 3/97.

Howe, Jeffrey C. 1991. Original Descriptions column: Melanotaenia maylandi. FAMA 8/91.

Howe, Jeffrey C. 2001. Original Descriptions column: Melanotaenia caerulea Allen 1996. FAMA 10/01.

Hutchings, James F. 1982. Another rainbow on the horizon (Glossolepis incisus). FAMA 1/82.

Korytko, Timothy P. 1997. The Red Rainbowfish. TFH 1/97.

Mayland, Hans J. 2000. Rainbows of Irian Jaya. TFH 3/2000.

Meinken, Hermann & W. Foersch. 1975. Iriatherina werneri, a new atherinid fish from New Guinea. TFH 4/75,

Richter, Jans-Joachim. 1983. Iriatherina werneri, the Featherfin Rainbowfish. TFH 8/83.

Richter, Hans-Joachim. 1985. The Magnificent Rainbowfish, Melanotaenia boesemani. TFH 8/85.

Richter, Hans-Joachim. 1986. The Banded Rainbowfish, Melanotaenia trifasciata. TFH 3/86.

Richter, Hans-Joachim. 1989. A neglected beauty- Chilatherina sentaniensis. TFH 1/89.

Sommer, Wolfgang. 1989. A new look at the Red-Spotted Rainbowfish, Melanotaenia fluviatilis. TFH 5/89.

Tappin, Adrian R. 1993. The original Australian Rainbowfish. FAMA 11/93.

Tappin, Adrian R. 1998. Rainbowfishes. AFM 7/98.

Tavares, Iggy. 2000. Iriatherina werneri, a Featherfin Rainbow. FAMA 11/00.

Tsang, Peter. 1960. Rainbow Fishes. TFH 11/60.


Allen, Gerald R. 1983. Kiunga ballochi, a new genus and species of Rainbowfish (Melanotaeniidae) from Papua New Guinea. TFH 10/83.

Elias, Jaroslav & Frantisek Podesky. 2000. The Forked-Tail Rainbowfish, Popondichthys (now Pseudomugil) furcatus. TFH 11/2000.

Elson, Gary. 1998. Adventures with Ol' Blue Eyes. TFH 10/98.

Richter, Hans-Joachim. 1983. Spawning the Popondetta (now Pseudomugil) Rainbowfishes. TFH 12/83.

Richter, Hans-Joachim. 1985. Pseudomugil gertrudae, a Blue-eye from "Down Under". TFH 10/85.

Tappin Adrian R. 1993. The pseudomugilids of Australia. FAMA 5/93.

Terceira, Anthony C. 1988. Pseudomugil mellis. A little known Silverside from Australia. FAMA 10/88.

Zurio, Georg. 1988. Small but fine. Popondetta (now Pseudomugil) species from New Guinea. Today's Aquarium. 1/88.


Baensch, Hans. 1972. The Celebes Rainbow Fish in Aquaria. Aquarium Digest International 1(2):1972

Richter, H.J. 1974. The Celebes Rainbowfish, Telmatherina ladigesi. TFH 12/74.

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