Instructions for keeping and breeding Cyprinodon (also a useful guide for Aphanius species)
By Michael Schneider, DKG 437. Photographs and english translation by Heiko Kärst, DKG 271 (October, 2012)
1.0 Water
If hard tap water is available (example: ph 7.6 / 580 μS/cm / kH 16.9 / dH 22.5) some additions must be mixed with the water. All following details relate to 10 litres water:
2g Gypsum
1-2g Sodium bicarbonate (NaHCO3)
1g Magnesium sulphate (MgSO4)
13g Synthetic sea salt
1 Drop Lugol’s solution
1.1 How to add?
The gypsum is stirred in a vessel filled with water. This dispersion is given into the aquarium directly after water changing. The water will be murky for 2 to 3 hours with no effect on the fishes. After this Synthetic sea salt, sodium bicarbonate and magnesium sulphate is added. Because our aquariums are run with Hamburg Fleece Filter (Hamburger Mattenfilter) I put the salt directly behind the filter fleece. The pump is doing the “stirring”. If other filter systems are used, than the salts should be disolved separately and added to the aquarium water. After this I add the drop of Lugol’s solution. My tap water I have a pH of 8.5 and a conductivity of approx. 3,800 µS/cm. Using softer tap water the amount of synthetic sea salt and sodium bicarbonate needs to be increased. Gypsum and magnesium bicarbonate do not have to be raised up. Slight changings in water quality are basically no problem according to my experiences because this might happen in nature, too.
2.0 Temperature
The tolerance against temperature changings is very high. The fishes endure temperatures between 10 and 32 °C without any problems. However these temperatures represent the lower and higher limit values for a short time. Usual temperatures for keeping and breeding are between 20 and 27°C. To keep the animal spirits I see a temperature changing between night and day of 2 to 6 degrees as essential. The aquariums are run basically without any heating. So the switching of the lighting causes temperature changing of 2 to 3 degrees which is already enough.
The correct hibernation is urgently necessary from my point of view. To do this it is advisable to find out about the conditions in the original habitats of the fish. Furthermore a shortening of the endurance of lighting to 8 hours a day is recommended to interrupt the breeding season in combination with a lower temperature between 15 and 18°C during winter time.
3.0 Keeping in Aquarium
3.1 Water changing
At normal stocking rate (look at 4.0) water changing of 60 to 70% every other week is important; at high stocking rate every week. Nevertheless an oftentimes water changing with lower amounts would be better.
3.2 Decoration
As a tank base, fine grained sand has proved itself, in a similar way a cover sheet might be used in a bird cage. Sand does not “cement”, has lime additions and avoids the infiltration of residuals. Calcareous stones and calcareous sand stones are recommended to build up structures and offer hideaways. Wood is possible as long its humid acids are eluted. Mangrove wood is unfit because of its ability to push the pH down to 6 or deeper. This endangers the fishes within the referred container. Salt tolerant plants can be planted but are not necessary.
3.2.1 Heating
In heated rooms any additional heating can be avoided. In unheated rooms it is optional whether heating is to be used or not. It maybe useful to get the fishes into mating conditions.
3.2.2 Filtration
Except in small containers for raising the offspring filtration is necessary. The system to use does not matter. All known systems work reliable.
4.0 Size of Container
Adult Pupfishes can be kept in aquariums with a content of 40 litres. A basic rule is to stock with a smaller number of fishes with smaller sized containers. Big container can only be used if enough specimens can be set in. If one would put three couples into a 200 litres aquarium this would lead to one or two specimens after some weeks. 200 liters offers much space for 6 fishes but not enough for 3 males to settle their own home ranges. They would overlap and the males would compete until death. The loss is guaranteed.
In tanks with a size of 100 litres or more Pupfishes can be kept together with tough Aphanius species like Aphanius sirhani, Aphanius danfordii or Aphanius persicus. In a community with other species the Pupfishes are not focused on their conspecifics and those containers can then accommodate 3 Pupfish couples. Other species get basically ignored, short competitions are the exception. Shall the Pupfish kept only with conspecific than their number shall be appropriate high, for instance 20 to 30 adults in a 100 litres aquarium. Short fights are possible, but proceeding without any damages mostly.
It is basically possible to keep several Pupfish species together. This claims an advanced knowledge regarding the specific characteristics of the species and the ability to differ the species especially the females of some species are very difficult to differ.
The other possibility is to keep the fishes in smaller tanks, mine measures 44x29x36 cm. Here the space is limited and aggressions are not excessive. In those aquariums 8 adult or 20 semi adult specimens can be kept if there are 3 or more males. Regardless the small tank size the fishes develop well and reach the usual size and morphology.
5.0 Keeping outside
I keep most of my fishes from April to approx. the beginning of October outside. They accommodate 75 to 90 litres mortar tubs, placed in a sunny site. I do not recommend to use stone containers because the store the heat and emit it during the night. This leads to an overheating during hot periods. Algae develops itself and should not be removed because this makes ideal spawning medium, providing shelter and food as well.
Some big calcareous stones are useful as equipment. The lime buffers the pH value that may drop down from rainwater it also provides the fry shelter. The water quality has to be checked, especially after heavy rain!
Depending on the stock density it is sufficient to change the water two or three times the season. It is important to check regularly. For fishes kept outside natural food is certain to be available as mosquito larvae, insects and algae. This is enough if few fishes are kept. Otherwise feeding is necessary.
6.0 Diet
Feeding is basically unproblematic. Artificial, frozen and live food is happily eaten. Nevertheless use quality food and provide a variety. Adult fishes tolerate one day without food a week. Some species eat green fiber algae (…as long as it is very fine algae, Thicker algae will be grazed but not eaten). Because of this do not remove algae. I prefer artificial food with a high content of Spirulina algae and living food, sometimes frozen food. During winter time feed less, depending on the temperature.
6.1 Diet in Winter
Above 17 or 18°C Pupfishes have a relatively normal need of food. It is reduced below this temperature. The fish have to be checked often to ensure they do not lose weight! It is normal that the fishes are not so agile and display paler colours. If they do not move or are laying on the bottom check the temperature if it is below 14 or 15°C, raise the temerature up to 18°C slowly.
7.0 Reproduction
The reproduction of Pupfishes can be done in a group, a trio or in couples. As spawning medium algae and filter floss are preferred while wool mops are mostly ignored. Many fry can be raised together with the parents if there are many spots to hide in the container. This type of reproduction is quit risky and should not be relied upon. It is important to conserve the stock at the same time using a more controlled manner. For an intensive breeding the spawning medium can be removed and stored in a separate container.
Breeding is possible in a 12 litre tank, but the fishes need to be watched. Some couples do not harmonise well and the male tend to chase the female too intensively. This can lead to the death of the female in extreme cases. Except the spawning medium one or two wool mops shall be put into the breeding container to provide shelter to the females. Couples have been separated before shall be separated in the breeding container by a glass panel for two or three days. Thus, the male will start its spawning activities a little calmer after the fishes have been put together. This is of particular importance if the female is much weaker than the male!
Female in good condition are able to spawn large amounts of eggs depending on the species. For example females of Cyprinodon veronicae are able to spawn 50 to 80 eggs within a couple of hours, while females of Cyprinodon elegans is able to spawn only 10 to 20 eggs. Once collected eggs have to be checked daily and infertile/fungussed eggs have to be removed. If this is missed, the total loss is risked.
7.1 Raising the fry
It is typically for Pupfish fry that they lay on the bottom for the first two weeks, they also get fed for up to two days by their yolk sacks. I put a bunch of algae into the container as their first food. Herein they find enough microorganisms to eat. After 3 to 5 days, depending on the species, I feed micro worms and after 3 to 10 days I feed brine shrimp nauplies. Fast growing single specimens can be put with their parents if they have reached a size of 20 mm.
7.2 Selection
The selection of weak or different specimens is not easily done, also at old stagers. Nevertheless it is an important task of the breeder. From a genetically point of view under aquarium conditions the species get pushed through a bottle neck within a few generations. If one is not ready to select peculiar specimens that differ from the phenotype, he risks to achieve a strain that is in no accordance with the originating fishes in its morphology. Specimens varying in body shape, fin shape, colouration and body pattern have to be selected like fishes with deformations as well. Eye-catching but weak growing specimens have to be positively selected also regardless of carrying all other specific features and being healthy. The nature is not cruel while selecting. Only by natural selection a species is able to stay alive. In captivity the selection has to be done by the breeder.
