On this page I'd like to discuss other livebearers which I'm keeping at home and which aren't mentioned in other categories on this website.
Here are some little guys among the livebearers zone. These guys are known as Tiger teddy, Teddy tiger and Neoheterandria elegans and are found in the Rio Truando in Colombia. They're really tiny. For a male reaches a body length of 1.5cm and a female up to 3cm body length. But note that "late males" do occur frequently. These late males will be significant larger in size till equal sized to females.
These fish should be kept in reasonably clean and still water at temperatures of at least 22°C till 26°C. For their physical measurements size allows to keep them in smaller tanks. Despite of the fact that I would like to see them swim in larger tanks, a small biotope offered by nano aquariums can be a beautiful eyecatcher as well.
They're really friendly fish but wouldn't keep them in a community tank for it may not be suitable for its shyness. Unless, the other tankmembers are small sized as well and for sure not aggressive. Otherwise they´ll get suppressed.
Further on, this species is a superfetative livebearer. So, no birth explosion in a short time. With this low number of offspring it's perfect if they're kept in a smaller environment.
Even though they are usually kept in neutral till hard water, the Neoheterandria elegans tolerates soft water without a problem (starting from a pH 6 and higher).
Above: An adult female (photo left) and an adult male (photo right).
A somewhat bigger cousin of the Neoheterandria elegans, is the Neoheterandria tridentiger.
The Neoheterandria tridentiger originates from the Pacific and the Atlantic coast of Central Mexico and the island of Tobago, located off the coast of Southern Panama, But it's mainly found in the quiet shady side streams and residual waters up to 2 meters deep, They occur in both fresh and brackish water.
As already stated, they're somewhat bigger in size than the Neoheterandria elegans. Males tend to reach 2-2,5 cm. And females tend to grow up to 3-4 cm.
Below: An adult female 9photo left) and an adult male (photo right).
Both sexes have 4-6 thin vertical bars on each side of the body. But these bars are not that explicit as those of the Neoheterandria elegans.
Another dwarf among livebearers is the least killifish (Heterandria formosa). Found in the southeastern part of the US. They also occur in swamp areas at the Keys in Florida. Which make them a perfect type of fish to be kept in brackish water as well. Even when it comes to temperatures which can be lower than average which is a good way to keep them fit. They'll do just fine at temperatures of 15°C till 22°C. And these rates are perfect to get them to breed unlike most other liverbearing tooth carps.
Both Neoheterandria elegans and Heterandria formosa deliver different from most livebearers. Most livebearers need just one copulation to impregnate a female for a couple of times. These guys need a new copulation every single time to realize a new pregnancy. Also the delivery as mentioned before is different. Do most livebearers deliver an outburst of young fry practically at once... These species will deliver one till three young fry each day for a period of one till two weeks. This species is a superfetative livebearer.
Above we see a week old Heterandria formosa (photo right) which was born in an outdoor tank. Like most fish also this young has grown faster than the offspring born inside the house.
Fry tend to have vertical bars o their bodies which will fade after a while and horizontal markings will appear afterwards.
Besides this version, there's also a golden version. The golden version does occur in free nature. And from time to time also with the captive H.formosas, a golden version will appear.
The ones I've started keeping come from a batch that were found in Stone river drainage in Charleston County, South Carolina (GPS coordinates: 32,920655,80.-23471).
Below we've a couple of swamp guppies (Micropoecilia picta / Poecilia picta). This species is also known as Scarlet livebearer, painted guppy, Poecilia picta and peacock livebearer.
These fish are in general hard to keep. Ever since this year (2011) my Micropoecilia pictas are doing really well again after a few months of disappointment with them. But I've started keeping M.pictas already in the 1990's. I've lost some adults but in some way I've got my third drop of fry of the ones which were left. And the offspring seem to stay fit just like their parents. I've noticed that these fish are kept best when the water is kept brackish. I hardly refresh the tank in order to keep them well. I even overfeed them on purpose. The food that's been left untouched seems to have a better influence on the condition of the water which they need. I only refill some water in case some water evaporates from the tank. With these fish just turn around the tradition to keep them well and bring them to a breeding level. The best temperature you can put these guys on is 28°C to keep then well. I've had these fish at lower temperatures but in some way that didn't work for them.
I myself am keeping mainly the red version. This red version the way they are bred in Thailand does not occur in the wild. There are wild specimens that are pale red till orange, besides the grey, yellowish, brownish and even plain specimens. But although my adult males are red and some females have a red shining on their bodies, the male offspring can become red or even have the wild coloring instead. So, no guarantee on that one!
An adult male can reach a length of approximately 2.5 cm and a female reaches up till 6 cm in length. It originates from South-America till Central-America. And to be more specific they occur in Surinam, French Guiana, Guyana, Trinidad & Tobago, Brazil and even Venezuela.
The female Micropoecilia picta looks a bit similar to a female guppy but actually it's got a slimmer body shape. Further on, the dorsal fin is situated a bit more backwards in comparison to a female guppy. Some have a peacock on their shoulders.
Above: On the right shows a grey wild colored male.
There's a rare phenomenon when it comes to reproduction. There are Picta females that reproduce as a regular ovoviviparous livebearer and there are Picta females which are superfetative.
What's also peculiar is when a Picta female is pregnant and almost due but at some point she's not comfortable to deliver, she may absorb the embryos through her body. This does happen to some other ovoviviparous livebearers as well. And it doesn't affect the female at all when she absorbs the embryos.
The Micropoecilia parae occurs in Guyana and Surinam. It inhabits fresh and brackish waters. Mostly in swamp areas and slow flowing streams like creeks. Firstly described by Eigenmann (1894).
In the beginning of the 21st century I had two couples of the Micropoecilia parae melanzona var red from an acquaintance of mine. And I got some yellow versions from somebody else who couldn't keep these fish alive. I've found out that he and the other acquaintance of mine had the same problem. Even I was struggling to keep them alive.
But the last male left was put together with a female blond endler and a grey female black bar endler. At some point there swam blond offspring in the fishtank and later on it turned out that those offspring were fertile hybrids of the blond endler and the Micropoecilia parae. The males had the typical red line on the side and the flame upwards in the tail just like the father had. Of the F1 came an F2 but with a grey base again and the red pattern on the sides remained.
But at the end I had still one specimen left of this strain. But again, it does prove that hybrids of far related species can be fertile!
Below: Adult males.
In the wild, the Micropoecilia parae comes in multiple color varieties. The photo below shows a yellow variety (photo from the internet). There are even specimens in the wild that are blend colored. With a marking somewhere on the body.
Below: Micropoecilia parae var yellow, males
The females look a bit similar to the females of the Micropoecilia picta.
Above: A number of adult and pregnant females.
Below: A juvenile female.
Size wise the Micropoecilia parae is similar to the Micropoecilia picta. Also when it comes to care, they're similar. Preferably kept in a species tank. For M.parae (just like most other Micropoecilia species) can become timid when kept with other fish which are more vivid than these. It may result in loosing them at some point.
They do well at temperatures between 22°C - 28°C and neutral till hard water.
Gambusia holbrooki / Gambusia affinis
A livebearer which has been distributed all over the world like the guppy has been, is the Gambusia holbrooki alo known as "Eastern mosquitofish" (Gambusia affinis is known as "Western Mosquitofish"). The genus name Gambusia is derived from the Cuban Spanish term "Gambusino", meaning "useless". The common name, mosquitofish, is derived from their use for biological control of mosquitoes, which itself was based on early observations that, in certain circumstances, they can reduce mosquito abundances.
The natural distribution of this livebearer knows a wide range from eastern and southern part of the United States.. They do occur in drainages where they inhabit brackish and freshwaters.
Left: A monument constructed in Sochi (Russia), honouring the western mosquito fish for eradicating malaria in the region.
Like the guppy, these livebearers have been distributed by man all over this globe as a biological mosquito control. The disadvantage of the mosquitofish in comparison to guppies is that they tend to nip at other fish's fins. Because of this and their predatory behavior they can do a real damage in time for the mosquitofish can be as prolific as most guppies are. So, a complete colony can do a massive destructing damage.
In general it's an easy to keep fish. They do even well in poor oxygenated water and a withstand a wide range of temperatures. So, even low temp rates will do the job. This all makes it also a good contender for outdoors like in a pond or tub. Considering the seasons we have overhere in Western-Europe, this fish is an outstanding livebearer to even keep them in outdoor ponds during winter. But be sure that the pond is sufficiently deep to survive the winter season. The mosquitofish is one of the best adaptable livebearers there is when it comes to water conditions. Therefore it's been so easy to distribute them all over this globe.
In their natural habitats, they do occur in more shallow waters where also a lot of insect eggs and larvae and invertebrates in general occur. But they also feed themselves with zooplankton.
Above: An adult male (photo left) and an adult female (photo right).
Males do tend to grow up to approx. 4 cm and females up to approx. 7-8 cm. In ponds and outdoor tubs they'll certainly grow up to these sizes without a doubt.
A lot of people think that there's a real resemblance with guppies. But actually anatomically there are sufficient differences between mosquitofish and guppies.
Anatomically there's not such a difference between G.holbrooki and G.affinis. Where the females of the G.holbrooki have a black marking above the belly area, the females of the G.affinis have a yellow-orange marking instead. And they females of the Gambusia affinis can have yellow blotches/markings on their body.
Above: The pale and speckled variety of the eastern mosquito fish.
Above: A summary of female mosquito fish. On the left are all Gambusia holbrooki females (totally lacking yellow coloring on the lower body or even head). | The left bottom female is a speckled female in a pregnant state. On the right we have all Gambusia affinis females . They all have this yelllow coloration on their bodies. The top right one does show a small black marking on the belly area but the rest is really yellow. It's also clear to see that the black stripe on the eye "can" occur in both Affinis and Holbrooki. Only the Gambusia holbrooki "can" (so, doesn't have to be) be speckled (both sexes but speckled females are rare. For in general, the females of the G.holbrooki are pale as well). The Gambusia affinis doesn't produce melanistic specimens. In the total period that I've kept G.holbrooki, there have only been two females born speckled. Their male offspring were speckled but their female offspring were normal pale ones. Didn't get any other speckled females ever since.
Left: Female splotched mosquito fish bred by Adrian Hernandez (Photo courtesy of Adrian Hernandez).
Below: A summary of male mosquito fish.
When it comes to the difference between the males of the G.affinis and the G.holbrooki, there's a difference in the shape and structure of the gonopodium between these two related species.
Above: (a) Gonopodium of Gambusia affinis and (b) Gambusia holbrooki, modified from Rauchenberger (1989). (c) Detail of the gonopodium of G. holbrooki from the River Quinto in San Luis Province. , the characteristic spines of G. holbrooki on the third ray.
Below: Mosquito fish that have been found in the Bahamas.
The Gambusia hurtadoi is a pretty and a quite peaceful species. Unfortunately, it belongs to the endangered fish species. Because it only exists in a single area of less than 4 km² in Mexico. The genus name Gambusia is derived from the Cuban Spanish term "gambusino", meaning "useless". The common name, mosquitofish, is derived from their use for biological control of mosquitoes, which itself was based on early observations that, in certain circumstances, they can reduce mosquito abundances.
In Mexico, it colonizes a pond called El Ojo de Hacienda Dolores and its drains. In comparison to other Gambusia species, this species is less nippy to fins of other fish.
Above: An adult couple (♀ upper fish), (♂ bottom fish) (photo right).
The front of this gambusia species is more round in comparison to other Gambusia species. Experiences with this species does differ a lot. There are keepers that found them pretty aggressive. But there are also keepers who haven't experienced any bad behavior. I haven't seen any bad behavior of them thusfar.
The photo below shows a couple of porthole livebearers (Poeciliopsis gracilis). A tooth- carp which can be found in Mexico up to Honduras. Just like the Girardinus metallicus this species isn't a bright colored fish as well for it's base is grey till beige. But for sure it's a fish with its own charm. Very typical are the 4 till 5 black spots on each side of the fish.
The males will become 4 cm in length and the females up till 6cm in length. A relative good range of temperature for these guys would be between 24°C and 27°C. Fish like these do need sufficient swimming space. So, keep the vegetation just to the sides of the aquarium.
The specimens that I have ever had came from two collecting locations → Rio del Oro (Mexico) and Rio Jaltepec (Mexico). I've been trying to determine the phenotypical differences between these two colonies. But it's still unclear. First I thought that the number of black spots would be the difference but both varied in the same range of black spots.
The Poeciliopsis gracilis is also a superfetative livebearer just like the other Poeciliopsis strains are.
Right: An adult female (top) and an adult male (bottom).
This species is also known as the golden livebearer.
This species is to be found in Central America: Creek near El Tuito in Jalisco, Mexico. And they're also to be found in tributaries of the Rio Purificacion near La Huerta, Mexico.
In nature they do occur in freshwater but also some areas where brackish water is running. By my own experience, I have to say that they tend to do better in brackish water in comparison to freshwater. They also like fast flowing water. I myself keep them with a bit more movement at the surface. Furthermore, they'll do well at rates of 20°C - 26°C.
They tend to reproduce after 4 weeks of gestation with an average number of 10 to 20 fry.
In general they are friendly livebearers but can show some dominance when kept with other tankmates which are a bit too friendly.
Max. size of a male up to 4cm and females up to 6,5cm.
It's not a bright colored fish but like every Poeciliopsis strain, it's an interesting livebearer to keep.
The Poeciliopsis baenschi concerns a superfetative livebearer.
The blackstripe livebearer (Poeciliopsis profilia) originates from northwestern Mexico where it's endemic to the east side of The Gulf of California. It inhabits shallow waters like streams, mangrove areas, estuaries and even brackish lagoons. Even though it's a freshwater fish, it also occurs in brackish waters as already been mentioned . It shows that also this livebearer is adaptable.
The name "Profilica" is derived from two Latin words which are "Proles" which means "offspring" and the word "Ferax" which means "rich'(referring to the number of many offspring they're able to produce). But they're also superfetative. So, the totally offspring of one batch will be dropped in a range of a number of days. This species has been first described by Miller in 1960.
This a small livebearer and so far known the smallest within the Poeciliopsis genus. Males tend to reach up to approx. 2 cm and female sup to approx. 3,5 cm. But from own experience, I do know that some females may reach up even larger till 5 cm. But that's just a very small percentage of all females that will become larger.
Above: An adult male (photo left) and an adult female (photo right).
Right: An embryo of the Poeciliopsis profilica at an earlier stage.
Left: Embryos of the Poeciliopsis profilica. The photo shows embryos at different stages. At image center is a late stage embryo with the network of blood vessels of the placenta. In the background are a one-cell embryo and embryos at earlier stages.
Below: An embryo of the Poeciliopsis profilica.
Below: A and B. Intact ovary removed from gravid female. Scale bar = 0.5mm. B. Outlines of the different embryos within the ovary shown in A. a. maternal/placental ovarian tissue complex (MPC) with late stage embryo removed, b. Very Late-eyed stage embryo (i.e. nearly full term, Stage 6), c. Early-eyed stage embryo ge 3), d.-f. Late-eyed stage embryo (Stage 5).
These small livebearer species are greyish till brownish colored with a dark lateral line on both sides. In their dorsal and caudal a partial yellowish is to be seen. The yellow fin coloration will be seen more clearly when light will hit those fins.
If not kept in a species tank, this species should be kept with friendly smaller fish. Otherwise, they'll become timid and will disappear slowly from the tank. They're also not demanding when it comes to water parameters. They can also be kept in softer water without any problems but start keeping them in soft water when they're juveniles or younger.
It's really hard to get your hands on this species. Mine were acquired by Klaus Tegelhütter.
Another livebearer which I'm keeping is the so-called leopardfish (Phalloceros caudimaculatus).The Phalloceros caudimaculatus in free nature is grey bodied with just one or two markings (depending on the location where they're found) on both sides of the body.
Most kept specimens are aquarium strains and are speckled. I've got 2 varieties : Phalloceros caudimaculatus reticulatus auratus (golden speckled) and Phalloceros caudimaculatus reticulatus (grey speckled). Besides leopardfish, they're also called one spot livebearer, dusky millions fish, speckled mosquitofish or speckled caudi. But I do have to mention again that these two varieties are not to be found in free nature. These are so-called aquarium strains. The original wild versions have got a wide range of distribution as shown in the picture below (red marked).
The wild version is also called one spot livebearer. This is a less slender build version of the ones we know as being an aquarium strain. It's greyish or golden colored and has got one or two blotch(es) on each side. Like the females shown below.
The blotched version as we know them within the aquarium scene are derived from blotched specimens that were imported back in 1905. The years after 1905, other wild specimens were collected from different locations and merged with descendants from the first imported specimens. This has caused that it's thusfar unknown from which location variety in the wild, the present aquarium strain came from. Not even in the first description by Hensel (1868), can be given any clarity about the exact ancestor.
When it comes to appearance they resemble a lot to the eastern mosquitofish (gambusia holbrooki). But leopardfish are a bit smaller (male → approx. 2,5 - 3cm, female → approx. 5cm) and they do have (as already mentioned) a golden variation. And they're less aggressive in comparison to the eastern mosquitofish but they'll remain finnippers just like the gambusias. I myself keep them together with my least killifish for they're shortfinned and an excellent combination.
Further more, there's a typical difference between male and female pattern, The males are much more blotched on their bodies then females.
Unlike the gambusias, leopardfish ain't that suitable for the control of mosquitos or other insect plaques for that reason. Not that they don't eat them but it doesn't seem to be their first choice...
Besides that they do extremely well in environments with rates above 20°C, they do also well in water rates starting from 8°C. Quite hardy fish which doesn't seem to bother about the water conditions too much. But also in free nature they're native to still streams and swamps with variable water conditions in Southern Brazil, Paraquay and Uruguay. Therefore, they're so easy to keep and adjust pretty well in most environments.
The golden version (Ph.c.auratus) is less common than its grey relative. To maintain a strong golden colour, it's recommendable to mix them with some greys.
Also this species can be kept outdoors during the better months of the year. This species will do fine starting at temperatures of 18°C and up. The photos shown below will show you some Ph.caudimaculatus reticulatus in my inflatable paddling pool (which I've made into a pond) in the backyard.
The reproduction is quite easy. And they won't chase nor eat their fry. This species can be kept with other friendly fish.
A not so bright colored livebearer which is also endemic to Mexico is the Priapella intermedia. Anatomically, totally different from most livebearers. What's really remarkable are they eyes. They've got a blue shimmer around the eyes which makes this livebearer very interesting.
This livebearer occurs in rivers (with a good water flow) with less vegetation in it. They occur with swordtails in their natural habitat.
They reach up to 5 - 7cm in size and do well at rates of 22°C - 28°C. A good water flow and a frequent water change is highly appreciated.
What's really remarkable is that it takes a long time before the genders are clear. So, even at a size of 4cm a male specimen with apparently female features can still develop the male features.
When kept with other fish, be aware of it that only friendly fish are compatible. If there's too much dominance coming from other fish, these Priapella intermedia will slowly disappear in the tank. And when it comes to a breeding plan, please be sure the tank ain't too crowded with other fish. These fish tend to breed better when kept with their own species.
Priapella intermedia is considered not being too prolific. After 4 weeks of gestation, just 5 till 20 fry will be born.
Another species within the Priapella genus is the Priapella olmecae. The Priapella olmeca has its distribution from the southeast of Mexico; Rio Agua Frio, Rio de la Palma, Rio las Maquinas, Lake Catemaco and neighboring lagoons. It inhabits both slow and fast flowing waters with less vegetation. The banks are shaded by overhanging scrub where they like to hang out.
This livebearer species will sex out pretty late. Also, the females hardly show a gravid spot. While they grow up between 4 cm - 7 cm (females become larger than males), quite often the sex determination is clear when they've almost reached adult size. So, you do have to wait quite a long time before you'll know what the sex ratio will be. Just like the Priapella intermedia, both genders have these blue eyes.
The Priapella olmecae makes a good shoaling and community fish in a tank. They're friendly fish and are mostly active in the mid region of the tank. What I've noticed from my own experience is that they like to hang out where the aerator is.
This omnivore can be kept at temperatures between 20°C - 28°C in neutral till hard water. The number of offspring of each batch is low till moderate. This has got to do with the fact that the newborn fry are approximately 0,8 cm - 1 cm in size.
This livebearer is to be found in Lake Nicaragua (also known as Cocibolca or Granada in Nicaragua) on the Atlantic drainage to the Rio Parismina (Costa Rica) and the Rio Tenorio drainage (Costa Rica) on the Pacific slope.
This is a slender livebearer, translucent till yellowish bodied. With a base of the first dorsal rays with a black blotch or some moe black in the dorsal. And those males also have a yellow marking in the dorsal and some vertical bars on their bodies. Something that misses out on the females.
They have wide range of temperature tolerance. They feel quite happy with temps of 18°C - 40°C. Which makes this livebearer interesting to keep outdoors as well during a certain period of the year.
After 4 weeks of gestation, a number of 10 - 50 fry will be born. And they'll size up to 6cm.
The Alfaro cultratus (also known as knife livebearer) occurs in Nicaragua, Panama and Costa Rica where it inhabits shallow waters like rivers (mainly shoreline), ditches and creeks with mainly a low till moderate water flow. But sometimes they also occur in fast flowing waters.
The genus "Alfaro" is named after zoologist Anastasio Alfaro and the subname "Cultratus" refers to the knife shaped body. The species itself has been described by Regan (1908).
Despite of the fact that they require a carnivorous diet, mine are already used to have also flake food made of greens. But a carnivorous diet remains preferable. They'll reach up till about 8 cm.
Knife livebearers tend to be timid for they like to hide between plants or ornaments. But once they are being fed, they turn into very vivid creatures. Best described as being ADHD torpedos in the tank. Once they're done eating, they become timid again.
In case one gets the urge to combine these fish with other species, be sure that they'll be sturdy build fish. For the knife livebearers can be nippy towards other species. But best to be kept in a species tank. They'll do well at temperatures between 22°C - 28°C. a ph between 6,0 - 8,0 and a gH between 90 - 357 ppm.
This is an ovoviviparous livebearer that can be found in Costa Rica and Panama. To be more precise: From northern Costa Rica to western Panama (small area), Atlantic and Pacific drainages; Costa Rica. The etymology of the fish of the genus Priapichthys is taken from Priape, the Greek and Roman god of procreation in mythology but also as a diminutive of the word phallus.
This livebearer is also known under its common name "Orange fin livebearer". The name orange fin livebearer has been given because both genders have an orange seam in their dorsals.
Above: Two adult females.
Lives in currents of low to high velocity; in brooks and streams between 25-1270 m elevation; in temperatures of 17-35°C. Swims in small groups at all depths, over rock or sand substrata. Reproduces continuously all year round. Feeds on terrestrial and aquatic insects, especially ants and termites. But mines are also accustomed to flake food. Because of the wide tolerance in water temperature, these fish are good contenders to keep outdoors during the better months of the year. Despite of the fact that they can reproduce themselves all year round, the batches of newborns won't be that large. Mostly between 5-15 newborns each batch.
They're not that demanding when it comes to the hardness of the water. They'll do well in moderate soft till hard water. They prefer shallow waters and will be active in all layers (as already stated).
Females tend to become larger than males. Females will reach up to 8-10 cm. And males tend to grow up to 5-7 cm. The males have a thin elongated gonopodium. Because of the shape and length of the gonopodium, these livebearers will hardly have a courtship. But most ovoviviparous livebearer species with an elongated gonopodium don't have a courtship.
Left photo: An adult male.
Scales bordered in black which gives a cross-hatch pattern to the body, more intense along the midline of the side and sometimes resembles a series of X's along the body, The sides with 6 - 12 vertical bars, more conspicuous on the urosome and the intensity varies according to the geographical region of the population. Black elongate blotches present on the membranes of the dorsal fin base. First anal fin rays orange; other fins colorless. Eyes and cheeks reflect silvery green highlight.
This livebearer species has the terminal, upward-facing mouth typical of surface feeders. And they've got a protruding belly.
This species is semi friendly. Wouldn't combine them with sensitive and too friendly fish. Best to keep them in a species tank or combined with more sturdy fish. The females tend to become aggressive towards males. Especially when they're pregnant. That why it's best to keep them in a well sized tank. So, that those males can withdraw when needed.
I'm keeping and breeding this livebearer species ever since October 2020. And I've got them combined with the Polkadot splitfin (Chapalichthys pardalis).
This wild livebearer species is well suited for the more experienced aquarist than for a novice aquarist.
A very vivid livebearer is the Brachyrhaphis roswithae. This species is named after Roswitha Etzel and originates from Panama. Brachyrhaphis stands for short needle and refers to the short gonopodium of the male.
It's quite a hardy and vividly fish which loves to swim in the upper zone where the water surface is a bit more vivid. So, no still water surface for these guys...
They're friendly with their own kind but they tend to be very dominant in their natural behavior among other fish. In such a case, you'd better combine them with other rigid fish. But better is to keep them in a species tank. Smaller fish will mostly become casualties of their biting habits. I've seen a couple of times that full grown specimens grabbed full grown endler females and bit them in half right away.
In order to give them the comfort they need, a bright open spot is appreciated.
The Brachyrhaphis roseni (also known as Cardinal brachy) occurs in rivers and streams (mostly shallow areas of these streams) with a rocky landscape and vegetation in Panama and in Costa Rica. The subname "Roseni" means honorific. Just like his cousin Brachyrhaphis roswithae, the B.roseni can preferably be kept in a species tank. Also this vivid but also nervous Brachyrhaphis species can show the dominant and aggressive behavior towards other kinds of tankmates. But they're okay with their own kind or even other Brachyrhaphis species. But to avoid crossbreeding, it's better to not combine them with other Brachyrhaphis species.
These fish will do fine at temperatures between 20°C - 28°C. At somewhat higher temperatures, they'll reproduce better.
The male stays a bit smaller but can reach about 5 cm and a female can max up till about 8 cm. Both genders are real good fry predators. So, keep in mind to be certain that sufficient hiding places for the fry is present if left in the adult tank.
Above: An adult female (photo left) and an adult male (photo right).
Both genders also have a black blotch behind their anal fin. This is not a pseudo gravid spot. For pseudo gravid spots only occur when the fish is maturing. So, in this case it's just a black blotch.
Above: Adult male (top) and an adult female (bottom).
As being real carnivores, they can be adapted to flake food. And sometimes they're willing to eat greens as well. But they'll remain carnivores.