ideal species of livebearing fish for small aquariums is the glassfish. After experience with it, it might be more accurate to formulate the opening sentence in reverse – the glassfish is not suitable for larger aquariums.
Its homeland is Cuba. First hunted for scientific purposes, it initially slipped through the meshes of fishing nets because of its small size. When later accidentally caught in a net with denser mesh, it was thought to be a juvenile of a different species. The author of the first scientific description, the American ichthyologist C. L. Hubbs mentions that it was not until 1934 (?) that ornamental fish hunters for aquarium purposes succeeded. It so happened that the scientific description came relatively late.
In the chronology of time, it is remarkable, as Hubbs notes, that American aquarists knew the species before 1934. (He mentions that La Torre named the species in 1933. It was described and figured in Peters’ 1934 aquarium publication) The author of the names Eptomaculata lara and Limia eptomaculata lara, which JACOBS assigns to synonyms of Q. atrizona in his 1969 monograph of the viviparous fishes, is supposed to be Troemner (1933). Since Hubbs would have had to accept the existing names of either author by right of priority, these were apparently invalid (nomen nudum) names. It is also possible that Jacobs’ indication is erroneous.
Distribution
There is also some confusion surrounding the original distribution. Hubbs, who was sent fish from the Everglades Aquatic Nursery to identify, hesitated for a long time to establish a spatial distribution in the wild without further investigation. In the end, he decided on information alone that the terra typica was the vicinity of Havana in the west of the island and in the east near the port city of Baracoa.
Despite the fact that the occurrence east of Havana has not been confirmed to date (!), this incorrect information has been uncritically described from publication to publication until recently. The distance between these localities as the crow flies is about 650 km (not, as Jacobs states in the cited monograph, “The type locality is Baracoa in close proximity to Havana”).
Hykes gives two localities: according to the Mexican fish collector Lara in the vicinity of Havana and according to Innes on Isla de Piños (today’s Isla de la Juventud – Youth Island).
Much later (1958), RIVAS proved the presence of a few specimens, sporadically found in small lakes in the southern drainage of the Sierra de los Organos and Isla de la Juventud, thus again in the west of the island. However, the species has not been recovered at historical sites for several decades. For a long time it was therefore considered probably extinct.
Occurrence
Fortunately, in 1977, Cuban biologists succeeded in discovering a new population on Isla de la Juventud (i.e. the area mentioned by Innes and Rivas) in Laguna la Jicotoa (Punta de Oeste). Thus, the current known distribution is in the western region of Cuba, but probably only in the single location mentioned. We should add that even this locality must be interpreted with some reserve. Several strong tornadoes have passed through Cuba in recent years. It is possible that they have also affected the distribution of the species, and the situation is now quite different.
The uniqueness of the species is confirmed by the fact that it has been a monotypic species (the only member of the genus) since its first scientific description. It is also rare that no expert has (fortunately) renamed the species, and Hubbs’ naming has endured for 70 years. Minor “cosmetic” modifications have occurred only in higher taxonomic units.
From Hubbs’ original inclusion in the subfamily Gambusiinae, tribe Heterandriini, the species was later removed from the subfamily Gambusiinae and reassigned to the tribe Girardinini. More recently, Lucinda and Reis, in a new classification of the Poeciliinae, propose its inclusion (along with seven other species) in the tribe Poeciliini Bonaparte, 1831.
Etymology
The unusual generic name quintana (Lat.) means belonging to the fifth. It refers to the original structure of the fifth ray of the gonopodium. The generic name atrizona (Lat.) – smoky black-banded – refers to the body pattern.
First experiences
According to OLIVA, the livebearing glasswort first entered the aquariums of Czechoslovak aquarists before 1939. However, it became extinct during World War II (1939-1945).
Aquarists know the urge to acquire a rare novelty. Well, even in me there was a desire to acquire the rarity of a rediscovered livebearer as soon as possible after a half-century of rediscovery. With the help of contacts and friendly help I got the fish from Cuba in February 1978.
My joy was great at first, but my disillusionment was even greater later. While my Austrian friends, for example, didn’t even want to believe that an aquarist in a socialist camp actually had this “extinct” species, they were extremely surprised and excited when I sent them the fish. An icy shower, however, came from Slovak breeders who (as with rarities many times before) showed absolute ignorance. Only thanks to a different attitude to novelties beyond today’s borders, in 1980 I obtained more specimens for the revival of breeding from a well-known breeder Mr. Vajdák from Otrokovice. I informed about breeding and rearing in foreign literature. Aquarists from the then GDR obtained probably the first fish (mistakenly labelled as Cnesterodon decemmaculatus), from the exhibition of the aquarist organisation in Karlovy Vary in 1981.
Baruš states without further specification that together with other livebearers he brought to the Institute for Vertebrate Research of the Czechoslovak Academy of Sciences in Brno (of which he was the director at that time) from Cuba also 5 specimens of the glassy livebearer. It is a common practice of the world’s scientific institutes that they willingly provide surplus fish from laboratory breeding to interested parties. However, the comrade academician selfishly forbade the Brno aquarist Mr. Váň, who kept all the species for his institute, any further distribution of unnecessary fish. He preferred to let the rare complete assortment of endemic Cuban livebearers become extinct.
Shape and colouration
The size of males is about 20 mm, females 40 mm. The body is compressed on the sides and, especially in males, except for the silvery abdominal region, glassy translucent. The individual vertebrae of the spine and the gas bladder are clearly visible. This transparency proved to be a problem when photographing body colouration.
The colouration of both sexes is yellowish to olive, with a whitish sheen in side lighting. There are 2-7 (up to 10 in females) unequally sized perpendicular bands on the flanks and a dot at the base of the caudal fin. The number of stripes depends, among other things, on the age of the fish. Their intensity also varies according to mood. There are also individuals with defective drawing. The fins are clear. The dorsal is edged black and has a crescent-shaped spot at the root. The outer edges of the pelvic and anal fins of females are bright white.
The gonopodium of males is very long and terminates in a downwardly curved hook. For catching, therefore, a glass trap (‘pipe’) is preferable to a net. This prevents the gonopodium from getting caught in the mesh and possibly damaging the fish with the tissue of the net. The structure of the gonopodium is relatively simple, but in contrast to other livebearers it has several segments turned to the left. Therefore, 90% of erections are left-handed. Copulation occurs when the female is in motion.
Keeping
Keeping is only successful in monoculture. We use small aquariums of 10 to 30 litres. Experience has shown that in larger aquariums, even when fed 3 times a day, they become malnourished over time. This is because in a larger tank, with more movement, the need for energy supply increases, and since they eat relatively little, they are permanently partially hungry. Experts say that the ratio of rescue and production rations has narrowed in the diet.
There are slight problems with feeding at all. The glassfish is one of the few species that does not like to eat the obligatory artemia. A “worm-like” diet – micras, grindal, slit tubifexes in combination with Tetraphyll or spirulina – has proven to be very effective. They nibbled on fine green algae with gusto. Sporadic articles by early breeders mention that the fish readily eat dry food. This may have been because they were then fed foods closer in composition to natural foods. I have not come across today’s ones.
They are peaceful in nature, but fragile, shy and curious at the same time. Even in monoculture, the fish are indolent and disappear in a flash among the plants whenever disturbed, only to reappear just as quickly at their usual feeding spot. It is advisable to plant the tank with fine-leaved plants. Ideally with a growth of fine green algae on the walls.
Normal tap water, total hardness 10 to 15 °dHG with a pH of around 7,0. Optimum temperature 22 to 26 °C. Higher temperatures or permanent rearing at the upper temperature limit is detrimental to the fish. The condition, especially of the females, is then poor and they do not fill out. With a regular change of 1/4 to 1/3 of the contents every 10-14 days, there is no need for aeration or filtering.
To confirm their colonization theory that some paleo-Poeciliidae may have gotten from one compartment to another via the sea, Rosen and Bailey did an experiment with live-bearing glassfish. They kept it in synthetic seawater for several weeks in the laboratory without any harm. Thus, in the case of treatment, we can use a relatively high concentration of salt.
Breeding
There is not much experience with rearing (after World War II) yet. In my breeding, at a temperature of 26-28 °C, the intervals between litters lasted between 41 and 45 days. The intervals of 24-41 days (average 28 days) reported by Baruš also seem to be indicative of fish rearing at a higher temperature. It is noteworthy that for a species accustomed to relatively high temperatures in its native habitat, the birth intervals at lower temperatures were surprisingly shortened. At 22-25 °C, the most common is 28 to 30 days. Normally it is the other way round – higher temperature, shorter intervals.
Adults do not notice the young at all, so it is enough to place a thicket of Java moss (Vesicularia dubyana) in the aquarium and a marbled moss (Riccia) on the surface. As Java moss acidifies the water quickly, we monitor the pH regularly. We then catch the newborn juveniles for controlled feeding.
The juveniles measure 5-6 mm, are strikingly slender and very shy. Their size increases with the size of the female. There are 3 to 20 young per litter, the number of which is not dependent on the size of the female. Parturition is completed in a maximum of four hours. Jacobs’ statement that ‘The young see the light of day individually at intervals of several hours, divided into a series of several days’ is completely erroneous.
The American scientists state that the species is not one of the superfetators. This has been confirmed from the very beginning by aquarium husbandry. It is therefore not even possible to agree with the assertion of the existence of a false, even typical, superfetation for Q. atrizona.
Older sources differ in the number of young born. Hykes mentions 8-30, German authors (Frey, Jacobs, Sterba) – 35-40, and finally Baruš 3-27.
The young need good feeding with live powdered food (emergency artemia) and micras. They will not survive the first week when fed dry preparations. Their growth is, with some fluctuations, rapid.
By the 3rd month, most males are sexually mature. In the 4th month (at the lower temperature in the 5th-6th month) the females are gravid.
Vienna specialist for livebearers Mr. H. Stefan, who got the fish from my breeding, strangely enough claims that we can expect the first young from the females only at the age of 10-12 months. Births at average intervals of 28 days reveal that he kept the fish at 22-25°C. His findings document how different experiences can occur in different rearing of the same material.
The above breeding observations apply to fish from the wild and 11 aquarium generations. It is possible that aquarium populations that have been adapted for a long time will behave slightly differently.