Tag Archives: Fish

2 (two) x Hermaphroditic Females of Kryptolebias marmoratus «Dangriga» (Belize)

The male is not required for breeding. They require brackish water – one leveled teaspoon of marine salt per every 2 liters of water. This species grows up to approx 50 mm in size.

The Mangrove Killifish or Mangrove Rivulus, Kryptolebias marmoratus, is a species of fish in the Aplocheilidae family. It lives in brackish and marine waters (less frequently in fresh water) along the coasts of Florida, through the Antilles, and along the eastern and northern Atlantic coasts of Mexico, Central America and South America. Our fish originates from Belize. It has a very wide tolerance of both salinity (0—68 ‰) and temperature (12–38 °C or 54–100 °F), can survive for about two months on land, and mostly breeds by self-fertilization. It is typically found in areas with red mangrove and sometimes lives in burrows of Cardisoma guanhumi crabs.

 

 

Kryptolebias marmoratus can spend up to 66 consecutive days out of water, which it typically spends inside fallen logs, breathing air through its skin. It enters burrows created by insects inside trees where it relaxes its territorial, aggressive behaviour. During this time, it alters its gills so it can retain water and nutrients, while nitrogen waste is excreted through the skin. The change is reversed once it re-enters the water.

When jumping on land, Kryptolebias marmoratus does a “tail flip”, flipping its head over its body towards the tail end. The rivulus’ jumping technique gives it an ability to direct its jumps on land and to make relatively forceful jumps. A team of scientists associated with the Society for Experimental Biology released a video in 2013 showing the jumping technique.

The species consists mostly of hermaphrodites which are known to reproduce by self-fertilization, but males do exist, and strong genetic evidence indicates occasional outcrossing. They are also the only simultaneous hermaphroditic vertebrates, and the concentration of males to hermaphrodites can vary depending on the local requirement for genetic diversity.

 

 

Kryptolebias marmoratus produces eggs and sperm by meiosis and routinely reproduces by self-fertilization. Each individual hermaphrodite normally fertilizes itself when an egg and sperm that it has produced by an internal organ unite inside the fish’s body. In nature, this mode of reproduction can yield highly homozygous lines composed of individuals so genetically uniform as to be, in effect, identical to one another. The capacity for selfing in these fishes has apparently persisted for at least several hundred thousand years. Meioses that lead to self-fertilization can reduce genetic fitness by causing inbreeding depression. However, self-fertilization does provide the benefit of “fertilization assurance” (reproductive assurance) at each generation. Meiosis can also provide the adaptive benefit of efficient recombinational repair of DNA damages during formation of germ cells at each generation. This benefit may have prevented the evolutionary replacement of meiosis and selfing by a simpler type of clonal reproduction such as ameiotic or apomictic parthenogenesis. Cannibalization of fingerling occurs, but only unrelated offspring. Kryptolebias marmoratus is considered to have potential as a bioindicator species of estuary habitats.

 

2 (two) x Hermaphroditic Females of Kryptolebias marmoratus «Dangriga» (Belize)

Pair of Aphyosemion australe «Cap Estérias BSWG 97-24» (Gabon)

The fish originates from Cap Estérias, Estuaire Province, Akanda National Park, Gabon. The original specimens have been collected by T. Blum, P. Sewer, H. Weder and R. Gluggenbuehl in July and August 1997.

Breeding is relatively easy, employing a spawning method known amongst hobbyists as «egg scattering». There exist several different methods of spawning it, and much is down to personal preference. A pair can easily be spawned in a tank as small as 12″ x 8″ x 8″. It’s often recommended that it should be spawned in trios, but brood sizes tend to be lower when it’s bred this way. This is perhaps due to the fish that is not involved in the spawning activity eating some of the eggs.

Many breeders do not use filtration in killi breeding setups but the addition of a small, air-driven sponge filter is good to prevent stagnation. The water should be soft and acidic with a pH of 6.0 – 6.5 (although there are instances of this species being bred in water of up to pH 8.0), and a temperature of 21°C – 24°C. Peat filtration is very useful and also keeping the tank unlit.

Sparring is common, usually gentle, occurs between males, and involves no risk of injury.

The fish should be conditioned on a varied diet of live and frozen foods. Many top breeders recommend keeping the sexes apart in separate conditioning tanks and selecting the best-looking male and plumpest female before placing them in the spawning tank. This method allows females to recover between spawnings. Eggs will be deposited either in the substrate or in clumps of vegetation in nature, and the spawning medium can therefore either be a layer of peat moss on the base of the tank, clumps of fine-leaved plants such as java moss or spawning mops. If you’re not using peat moss, a bare-bottomed setup is best, for both ease of maintenance and egg collection.

If water conditions are good and the fish are well conditioned, spawning should present no problems. The eggs can be left in the aquarium to hatch with the parents but some may be eaten. If you want to raise a good-sized group, the eggs should be removed. 10 – 20 eggs are deposited daily for around 2 weeks and these should be removed gently as they are noticed. Each pair should only be allowed to spawn for a week or so before being returned to the conditioning tanks, as the spawning process is hard on the fish (particularly the female) and they can become fatigued and weak if left for too long.

Once removed the eggs can be incubated either in water or by placing them on a damp layer of peat moss in a small container (margarine tubs are ideal). In our experience, fewer eggs tend to fungus using the latter method. Whichever you choose, always remove any fungussed eggs as you notice them to prevent the infection from spreading to others.

If incubating in water the eggs can be transferred to a small aquarium containing water from the spawning tank to a depth of 1-2 inches to which has been added 1-3 drops of methylene blue, depending on volume. This container should be kept under darkness (the eggs are very sensitive to light) and checked daily for fungussed eggs, which can be easily removed using a pipette. They will hatch in 10 – 20 days depending on temperature.

If incubating on peat moss place the container in a warm, dark place and simply leave it for 18 days, after which the eggs will be ready to hatch. If you are spawning several species or multiple broods it is a good idea to label each container with the date, hatching date, species and number of eggs to prevent any disasters. Hatching can usually be induced by simply placing the eggs in the raising aquarium after 18 days, as the wetting of the eggs generally stimulates hatching. If this fails, blowing gently into the water through a straw or piece of airline can trigger hatching.

The fry are tiny and initial food should be infusoria. If using the peat moss incubation method, the raising tank can be ‘seeded’ a few days prior to hatching by adding a couple of drops of liquifry or green water. Otherwise, add small amounts as required. After 2 days they can be fed brine shrimp nauplii or microworm with the introduction of larger and frozen varieties after 2 weeks or so. The water must initially be kept very shallow but the level can be raised as the fry grow.

Extreme care must be taken regarding water quality in the raising tank as the fry are very susceptible to velvet disease. They should be fed twice a day with small water changes every 2 – 3 days for the best growth.

Species Summary:

  • Scientific Name: Aphyosemion australe (Rachow, 1921)
  • Population Code: Cap Estérias BSWG 1997-24
  • Collectors: T. Blum, P. Sewer, H. Weder and R. Gluggenbuehl in July and August 1997
  • Location: Cap Estérias Department, Estuaire Province, Akanda National Park, Gabon
  • Subgenus: Scheelsemion
  • Species Complex: Calliurum Group
  • Subfamily: Nothobranchiinae
  • Family: Nothobranchiidae
  • Disposition: Active, Peaceful
  • Total Length:  50 – 60 mm
  • Spawning Method: Egg Scatterer
  • Breeding Proportion: 1M : 1F / 2F
  • Breeding Difficulty: Less Demanding
  • Incubation Period: 10 – 15 Days at 22°C – 23°C (water incubation) and 15 – 20 Days at 22°C – 23°C (semi-dry peat moss incubation)
  • Fry Size: Small (require Infusoria as first food)
  • Sexual Maturity: 6 – 8 Months
  • Life Span: up to 3 years (depends on food and keeping conditions)
  • Filtration: Moderate
  • Water Changes: 1/3 Biweekly
  • General Hardness: 5 – 12 dGH
  • pH: 5.5 – 6.5
  • Temperature Range: 21°C – 24°C
  • Lighting: Moderate Light
  • Diet: Live and Frozen Food
  • Keeping Difficulty: Less Demanding

 

Pair of Aphyosemion australe «Cap Estérias BSWG 97-24» (Gabon)

Pair of Aplocheilus dayi «Sinharaja» (Sri Lanka)

The Ceylon Killifish (Aplocheilus dayi) is a species of killifish endemic to Sri Lanka. Aplocheilus dayi is one of the easiest killifish to keep and breed. They will eat flake food and are content to occupy the surface of a community tank. You can start your colony having just one breeding pair. The adult fish grow up to 8 – 9 cm if kept in a spacious aquarium and fed well on varied foods preferably live ones. Both sexes have a black dot at the rear end of the base of the dorsal fin.

A group of 10 fishes can be successfully kept in a 100-liter aquarium having a large sponge filter. No other décor is really required, except for the requisite tight-fitting lid. The spawning medium is a 5 – 6 cm long mop of green yarn with a slightly coarse texture, clipped to the top of the tank for easy removal or to a floating cork. For the best result, it is recommended to feed the breeding fish with live Artemia, Glassworm and Daphnia, although they will take frozen and dry foods. They eat with a vigorous snatching motion that is typical for surface-dwelling killifish. The temperature should be 24°C – 26°C with approximately 50% water changes every two weeks or whenever the waste built up.

After a few days of getting acquainted the eggs will be laid daily so that you have to check the mop and remove the eggs to avoid their predation. While spawning the male drives the female into the mop with a sideways pushing motion, and then the pair shakes as the eggs are released and fertilized. The eggs are 1 to 1.7 mm in size and hard to the touch. Pick the eggs and put them in clear plastic cups, so that fungus or development of eyes would be easily visible. To discourage the growth of fungus use a very strong solution of methylene blue, about two drops per cup.

Collect the eggs in batches of 7 to 10 days, letting them all soak in the chemical bath for a few more days before pouring off the blue water. Then put the eggs and fresh water in a shallow plastic container. Depending on the temperature, the eggs would start to eye up after about 10 days and hatch in 14 days. The fry are large enough to scoop up with a tablespoon or catch with a medicine dropper. Force hatch any eggs that had eyes, but had still not hatched after a couple of weeks by putting them in a jar with a little water and breathing into it before shutting the lid tight for a few hours.

Raise the fry in a 5-liter plastic container with an airline (gently aerated small sponge filter) and some java moss to provide cover and microbes for snacking. A killifish fry box works well with a little peat/coir and dried oak leaves in the bottom to condition the water and give the fry hiding places, and a ramshorn or other snail to clean up uneaten food and to provide food for infusoria.

The fry can be fed microworms and freshly hatched baby brine shrimp (BBS). In a few weeks transfer the fry to a 30-liter growing tank with a good sponge filtration, java moss and java fern, and a dimmed light above. The fry grow quickly on twice daily feedings of fresh BBS. The males began to develop their distinctive bright yellow-gold colour around 30 – 40 mm.

Use sand at the bottom with little addition of coir or peat and oak leaf litter. In about 5 – 6 months they can be transferred to a large breeding tank.

Species Summary:

  • Scientific Name: Aplocheilus dayi
  • Describer: Steindachner, 1892
  • Family: Aplocheilidae
  • Origin/Locality: Sinharaja (Sabaragamuwa Province, Sri Lanka)
  • Common Name: Ceylon Killifish
  • Disposition: Active top-dweller, recommended a species tank
  • Total Length: 80 – 90 mm
  • Spawning Method: Egg Scatterer
  • Breeding Proportion: 1M : 1F / 1M : 2 F / Large Group
  • Breeding Difficulty: Fairly Easy
  • Female’s Daily Clatch: 5 – 15 Eggs (depends on the female’s size and water conditions)
  • Incubation Period: 10 to 14 Days at 25°C – 27°C
  • Fry Growth Rate: Fairly Fast
  • Sexual Maturity: 5 – 6 Months
  • Life Span: 3 – 4 Years
  • Water Quality: Ordinary Filtration, 1/3 Water Changes Every Two Weeks
  • General Hardness:  5- 15 dGH
  • pH: 6.0 – 7.0
  • Temperature Range: 24°C – 26°C
  • Lighting: Dimmed Light and Dense Planting
  • Diet: Live and Frozen Foods (will normally accept dried foods too)
  • Keeping Difficulty: Fairly Easy

Pair of Aplocheilus dayi «Sinharaja» (Sri Lanka)

Auction: 45+ Well Developed Eggs of Endangered Ophthalmolebias constanciae «Barra de São João» (Rio de Janeiro, Brazil)

Offering 45+ well-developed eggs of the endangered killifish – Ophthalmolebias constanciae «Barra de São João» (Rio de Janeiro, Brazil). The eggs are ready for wetting. The auction starts at 0.99 GBP! We ship worldwide.