Francisco Casado It is not my purpose in this article to make a purely scientific description of this genus of fish but to transmit my practical experience with them, trying to give guidance on the day to day maintenance. One more of the many expert opinions that exist. Nothobranchius is a Genus of the family Nothobranchiidae of the order Cyprinodontformes that is popularly included in the confusing group of killifish that includes such disparate genera as Aphyosemion, Epiplatiys, Rivulus and so on. Currently, 96 accepted species are recognized in most cases, but in some there is no unanimity. At the end, those that exist today are listed. It is often said in some aquarium publications or by some individuals that they are easy fish and indeed some species can be kept in isolation without problems due to their short life span and wide range of water values, but it is quite another thing to dedicate yourself to Nothobranchius, breeding them and keeping them for several generations,it is, more than difficult, very meticulous with the need to spend a lot of time on them and an almost constant vigilance, as an example, in only one day, due to a sudden water pollution as the most common cause, a small aquarium with 30 fry can fail. Apart from the labelling of the egg bags, Oodinium (as we will see later on)... definitely not the fish recommended if the aim is only to observe some beautiful aquatic animals. The future of Nothobranchius, like so many other animal species, is quite compromised by natural reasons, climate change or human action. In captivity or as we commonly call it in the "hobby" as well as being logically related to their natural biotopes, they have in the shorter term an uncertain future due to the ever stricter rules for shipment of species or transfer. Here in Spain, a so-called “animal welfare law” has recently been approved whose scope to the world of fish and much more to the Nothobranchius is very uncertain today but certainly unflattering. The problem is that when it comes to a point as specific as in this case of the Nothobranchius, the lack of knowledge of the legislators is very little or non-existent and surely other aspects such as its conservation and possible reintroduction into nature, for example, will not be taken into account. Surely if a species has become extinct in its habitat, reintroducing it would have little success because it would disappear again but keeping them in captivity would give the option to establish reintroduction programmes in biotopes or similar areas as well as to protect those areas where there are still species living as for example the great work of Nagy Bela trying to protect together with the natives of the place the area where N.polli lives very deteriorated by human activity. After this introduction we go with my maintenance and breeding experence. As I said, simply one more of the many that there may be with equal or greater success, based on more than 35 years of experience with this type of fish. The method depends on the time, space and other conditions that each person may have. I would define mine as an “artisanal” method to maintain and raise Nothobranchius, with multiple changes along the way. It is not a static installation, I just want it to be as practical as possible within relativity. As is almost always the case, I started keeping a mix of killifish mostly from the Brithis Killifish Association (BKA) members. , but soon the NotobranchIus became my exclusive dedication, fascinated by their life cycle, the origin of where they come from..., it was a way to have a piece of deep Africa at home.It was a time of great collecting trips starring Brian Watters, John Rosenstock, Ian Sainthouse among others. At first I tried to keep them by imitating their living conditions in nature, but the Nothobranchius habitats are very dynamic and variable and when I began to accumulate more species that became practically impossible, so I chose to keep them in standard conditions except for a few species that have a notable difference of life in their habitats. The standard conditions referred to are water between neutral and slightly alkaline. In my area the water is rather soft so I add a small amount of salt which also serves to prevent Oodinium. The temperature between 21 and 28 degrees with a wide variability due to the room where I have the fish that oscillates noticeably between summer and winter. Adding salt at a rate of one teaspoon per 8 liters from when they are one month old because according to my experience it favors them and in a certain way prevents oodinium, (one of the main enemies of the Nothobranchius to which I will dedicate another section), also to compensate for the GH of the water, which in my area is rather soft. My Nothobranchius aquariums are rarely kept with the same species for a full month because Aquarium changes are very frequent for various reasons such as the separation between males and females during their growth, size disproportionate, etc. For this reason, filters almost never fulfill their biological function and I use them rather as a mechanical filtration element. They are small sponge filters placed in a corner with a weak flow rate. The water does not contain any additives, only the aforementioned addition of salt. LOGISTICS My aquarium installation consists of approximately 40 aquariums ranging between 10 and 40 liters in addition to about five or six fifty-liter containers that I use for spawning larger species. For the hatching of the fry and growth in the first days I have one-litre and five-litre containers. The filters are sponge filters, small in size with a low water flow rate and fed by an air pump which also supplies the brine shrimp, hatching containers and smaller fry aquariums, these with minimal dripping. The plants I use are only of the Microsorum genus, mainly the Pteropus species due to its great resistance even withstanding some salinity of the water. They are not planted in the substrate, I place them in small pots or simply loose in the aquarium. The snails are of the Planorbis Genus, also very resistant. They are essential, especially in the first days of life of the fry, creating infusoria and, above all, contributing to the cleaning of the container by consuming possible brine shrimp from the bottom. I have not found that they eat the fry if they are in good condition despite being small containers of 1 or 2 liters, but I nevertheless avoid having snails in the reproduction aquariums because I have seen them eat eggs from the substrate. WATER COMPOSITION The water composition in Nothobranchius plays a relative role as long as it's not extreme due to their adaptation to different values. The water in my area is rather soft with a GH of five. It's probably not the best for Nothobranchius considering the values in their natural habitats, but it can be compensated for by adding, as I mentioned before, some salt and a pH booster because in aquariums without a biological filter, the pH can quickly drop, which can be deadly, especially for fry and very young fish if the values are below six approximately. I use fifty-liter barrels to filter and let tap water rest, allowing chlorine to evaporate. However, if there hasn't been enough time for this, I add some product to remove it. In my experience, tap water, even without chlorine, slows down the growth of fry, and it's much more advisable to use somewhat aged water. Alternatively, if I don't have aged water available, it works very well to add a small amount of water resulting from boiling peat. FEEDING. Feeding is an important point in the success of breeding Nothobranchius because of their need to eat continuously due to their short life cycle and their very fast metabolism (two hours after feeding, food is no longer perceptible in the stomach). They are not fish to be fed "occasionally" and they need to be fed 2 or 3 times a day. If this requirement is not met, the young fish will grow weak and will not reproduce and the adults will do so with very poor results. A total fast for a week (for example due to absence on vacation) is preferable to feeding them continuously but in a deficit. I feed adult fish mainly with live or frozen Bloodworms and Grindal and Enchytreid worms. There are hobbyists who have managed to make them eat dry food but I have rejected that option because I have tried to give them a diet as similar as possible to the place where they live in the wild and also because it requires a period of adaptation which in my case due to the volume of the installation is not possible for me due to the time it takes. I supplement the diet occasionally with small flies of the genus Drosophila, generally the wingless melanogaster of which I always keep some culture, small pieces of boiled mussel which they devour, and even small pieces of raw beef heart without excess because of the rapid water pollution they cause. Finally live artemia even if they are adult fish just to keep them active and to give them something to catch… I understand that amateurs who have few species can delve deeper into other types of feeding, but in my case and due to the volume, I have to look for maximum practicality and the shortest time possible and the fish are healthy and reproduce well with this feeding method. Special mention for the N. ocellatus which, due to its large size and voracity, differs above all in quantity. The base in this case is mussels cooked in relatively large pieces, raw beef heart, bloodworms, tubifex and adult Enchytreids. If I have availability and why not say so, I also supply them with small fish without the possibility of progression as would happen if they were wild. BREEDING. For reproduction, I preferably use 50-liter non-transparent plastic containers, placing coconut fiber in a glass bowl as a substrate. Preferably, and if I have enough availability, I place the fish to spawn in groups that for that size container would be for example, five males and ten females, with the obvious exception of large species such as N. ocellatus, orthonotus etc. With these large species I use a single male with three or four females, changing the male if possible every 15 or 20 days. This is for two reasons; to avoid inbreeding as much as possible and for the wear and tear of the male in his tireless reproductive desire. it is remarkable how much semen the males produce to be able to fertilise so many eggs in such a relatively short time. If the females have been emptied of eggs and I have free aquariums available, I take them out to try to help them recover, which normally happens except for some species such as N. Furzeri, which rarely fill up with eggs again. When choosing the specimens to reproduce, I take care that they do not present malformations or have striking color differences compared to the rest to prevent them from evolving towards a color different from their type locality. There are species or populations of Nothobranchius whose variability is minimal even if their natural biotopes are several kilometres apart, but there are others such as N. hassoni whose variability can be great in captivity, possibly because this species is still at an early stage in its evolution. As an example, from the Bunkeya population I have specimens with a red stripe on the tail, orange, intermediate or practically non-existent. In this case, and given that in their wild biotope the same thing seems to happen, it would be best not to opt for a particular colour that we like more than another, trying reproduce a varied group of them if possible. Of course and as a code of ethics, it should be prohibited for any Nothobranchius keepers to reproduce specimens from different populations even if they look the same. There is no accountability to anyone but we should be extremely meticulous on this point because, fortunately, with the possibility of exchange, purchase or sale, a species or population can be totally undermined. Finally, the bowl where the eggs have been deposited is removed every seven to ten days. There can always be eggs in the peat that has been spilled on the ground, but I have found that their viability is low, much lower than those deposited in the glass bowl, so I discard that part of the peat. HATCHING OF THE FRY Nothobranchius have the advantage that, being annual fish, their birth can be somewhat planned, allowing for the possibility of scheduling around potential absences due to vacations or other reasons. For the hatching of the fry, I use small aquariums of one or two liters, depending on the amount of peat, filling them before adding the eggs, making sure they contain approximately one to one and a half centimeters thick layer of peat added to the container. If it is less, I add boiled peat or coconut fiber until reaching that thickness. The eggs tend to sink to the bottom, but to prevent any from floating with the peat that does not sink, I stir everything. There may still be some peat floating, which I remove with a small net, then, I add half a dissolved oxygen tablet to the water, stirring everything again. The addition of oxygen has been used by me for many years to prevent belly sliders with a success rate very close to one hundred percent. Only in eggs whose fry are already extremely weakened either because too much time has passed incubating or, on the contrary, because it is too early to wet them, this method may not be successful. The cause for which fry can stay in belly slider has always been a matter of discussion, and although there are several studies on the subject, there is no fixed rule, with storage and incubation of the eggs likely having a very direct impact. However, in practice, this explanation falls short. Faced with the risk of potentially losing a species (one of the reasons mentioned earlier regarding the meticulousness involved in breeding Nothobranchius), I always use the addition of oxygen. The fully formed embryos in the egg wait for a reasonable period of time before they hatch, after which they gradually weaken. This period is likely conditioned by the specific conditions of each species in its natural habitat, but generally, it is not very long, although they may eventually hatch, they are practically unrecoverable fry. Depending on the maturity state of the embryos, hatching can occur anywhere from one hour after wetting the eggs to 24 hours later, rarely longer except in isolated cases. Once they have hatched, I leave them in the same container for one or two days, adding some newly hatched brine shrimp if they are large enough to capture them, or infusoria. After that time, I transfer the fry to another container of the same size, preferably with the same water they hatched in. If the water is becoming polluted, I place them in aged water from another functioning aquarium. The method for transferring them is simply pouring the water with the fry directly into the other container or scooping them up with a small net and adding them to the water. If there are unhatched eggs, the peat can be collected to dry it out for another month. There is an important objection at this point because sometimes in the bag, the eggs ready to hatch are uniform, but in other cases, there may be eggs ready to be wetted, others completely clear, and others intermediate. In my experience, these latter ones can be lost when drying them again. Ideally, we should wet only the eggs that we see ready to hatch, with the consequent extra time that entails. SEXING Male Nothobranchius typically start to colorize approximately one month after birth. Generally, the process is progressive, with each individual reaching its own coloration around one and a half to two months. There may be some exceptions where specimens initially show aberrant coloring compared to their typical coloration but eventually display their normal coloration. Experts in genetics undoubtedly have the explanation for this question. The male-to-female ratio, known as the "sex ratio," can vary among species, but generally it is acceptable for maintaining that species or population. However, there are occasions when we lose a species because all or almost all individuals despite being numerous, are either all males or all females, or there is a highly imbalanced ratio. This happens quite frequently without a clear reason. There are several assumptions, all unconfirmed, and one of them, perhaps the most plausible in my opinion is that the worse the water quality, the more females appear because a greater quantity of eggs is needed to perpetuate the species. In response to that issue, there is a theory that has been the subject of some studies which I personally also explored some time ago It involves attempting to ensure a pair by isolating fry in pairs from a very young age. In that case, they would be male and female. According to my experience with this practice, I was able to confirm that indeed the result is positive in the majority of cases, although not in all, approximately in 70 percent. This percentage is more or less consistent with the results of other experts.The condition is to separate them from a very young age (3 to 7 days). I am unaware of the definitive mechanism for why this occurs. Apart from unproven scientific considerations such as possibly hormones released in the container, etc., it's as if the fish tell each other, "there are only two of us, or we are pair , or the continuity of the species ends." It's a very "cinematic" assumption, but perhaps not too far from reality. EGG STORAGE Once the eggs have dried, on top of newspaper, store them in plastic bags, and inspect them after 7 to 10 days to check if they are fertilized. With N. ocellatus, it takes more days because eggs that seem viable at 10 days can spoil later Once the number of fertile eggs is confirmed, they are permanently stored in bags, labeling the contents and marking the approximate number of eggs it contains. I don't seal the bag so that I can examine it if necessary during incubation. The moisture level of the peat (or coconut fiber in my case) theoretically should be related to the amount of time that passes in their habitats until the next rainy season, although one must consider the complexity of the Nothobranchius cycle and how variable these parameters can be. Theoretically, the longer the period without rain, the more the soil dries out. However, at least in captivity, I haven't noticed significant differences between keeping it more or less humid. The incubation temperature of the eggs is the same maintained in my fish room, which fluctuates between 20 degrees on the coldest days of winter and 28 degrees in summer. At this temperature, most of the eggs typically remain unembryonated during the winter, and I have the problem that many species are ready to hatch within a short period, usually between March and May. As a result, I have many empty tanks in winter and many full ones in summer. If the temperature were more uniform, around 23 to 24 degrees, the eggs would follow their standard incubation time for each species and would be better distributed. However, I prefer to maintain this management plan due to the reasons already mentioned, to seek a balance between their life in nature and practicality. There are people who 'force' incubation by placing the eggs in incubators or even keeping them continuously in water without a drying period, which I don't see any utility in, except for impatience when dealing with only a few species. Additionally, I have found that with those methods, the possibility of the fry not reaching swimming stage is considerably higher.. It's important to keep a comprehensive record of the eggs stored, including their origin and the exact species and population names to avoid errors and completely distort the data when distributing them later on. We can easily turn a N.ugandensis Giligili into a N.ugandensis Butiaba or worse cases, which can persist and spread in the hobby if not careful. DISEASES In the section on diseases, one stands out notably, and that is Oodinium (Pisciodinium pillularis). It is often said that there is no good Nothobranchius without Oodinium, but my motto is different, and it is that to breed a good Nothobranchius, it must be free of Oodinium. It is a parasite that is latent in many aquariums and manifests itself when there are favorable conditions such as overpopulation, accumulation of organic remains, etc. The best way to eradicate it is prevention, but if it appears it is very important to detect it in the first few days. I conduct almost daily visual inspections, and if I detect its presence I treat it immediately with a specific medication for protozoa and doubling the dissolved salt quantity. If I normally maintain all Nothobranchius with a salt ratio of one tablespoon per 8 liters, as a treatment for Oodinium, I double that amount. The method is risky, and it requires close monitoring of the fish and not exceeding the time because they can die, but it's the only way I've seen to treat advanced Oodinium. The most effective medication is probably copper-based, but I don't use it because these fish are extremely sensitive to this element, and precise measurements are necessary to avoid exceeding the dose. Fortunately, it is rare for newly hatched fry to suffer from an Oodinium attack although it has also happened to me and in this case it is almost fatal if the parasite is already widespread. Increasing the temperature, keeping them in darkness... are some recommendations that many hobbyists have suggested for eradicating Oodinium, but I have not put them into practice due to the difficulty of doing so in a large installation. Currently (2024), it seems that it is not a worrying disease, but not long ago there was a quite extensive infection in the hobby, an intestinal parasite, Glugea sp, which was much more deadly than Oodinium and for which there is no cure. I know of specialists and enthusiasts of Nothobranchius who chose to get rid of all the fish and start from scratch because it is also extremely contagious. It was probably introduced into the hobby through wild captures, but fortunately, it seems to be in remission currently. The disease of white spot (Ichthyophthirius multifiliis) is rare in Nothobranchius and has the same consideration and treatment as Oodinium. Not exactly a disease, but intestinal blockage is not rare in these fish due to their voracious eating habits. FINAL CONSIDERATIONS The ability to have and maintain this wonderful world of Nothobranchius in captivity would not be possible without the numerous collecting trips to their places of origin, with the added scientific value provided by many people over the years, whom I won't list here to avoid forgetting anyone. These trips, in addition to feeding the hobby, contribute with great scientific value, as I mentioned, to understand how these fish live and evolve in nature, with discoveries of new species, etc At this point, however I also want to comment that although taxonomy is absolutely essential, in my opinion too many species are described that morphologically present few differences. Molecularly, these differences may be more notable, but they are constantly evolving, and it is very difficult to establish boundaries. Interestingly, in Nothobranchius, there are no described subspecies as in other groups of animals such as insects and birds, which in principle and in some cases should be the precursor to being considered a new species. There's a phrase that my old Natural Sciences teacher used to say many years ago, and I embraced it immediately: 'If animals knew the lengths humans go to in order to name them, they would die of laughter.' Nature is an interconnected system where living beings and their environment interact in a single balance, and their evolutionary process is continuous, making it truly difficult to establish separation boundaries. It's very likely that there are undiscovered species of Nothobranchius, and each collecting trip is an opportunity to find another wonder of this spectacular and interesting Genus of fish. To contribute to their maintenance in the hobby, the 'Nothobranchius Maintenance Group' (N.M.G.) was created, which is still active today. There are many possible studies to be carried out either through this group or any other initiative, such as explaining the breeding behaviors in captivity, determining sexes, and in nature, gaining a better understanding of the mobility that takes place in different species due to natural conditions. CURRENTLY RECOGNIZED SPECIES Nothobranchius albertinensis Nothobranchius albimarginatus Nothobranchius angelae Nothobranchius annectens Nothobranchius attenboroughi Nothobranchius balamaensis Nothobranchius bellemansi Nothobranchius bojiensis Nothobranchius boklundi Nothobranchius brieni Nothobranchius capriviensis Nothobranchius cardinalis Nothobranchius chochamandai Nothobranchius cooperi Nothobranchius derhami Nothobranchius ditte Nothobranchius eggersi Nothobranchius elongatus Nothobranchius fasciatus Nothobranchius elucens Nothobranchius flagrans Nothobranchius flammicomantis Nothobranchius foerschi Nothobranchius furzeri Nothobranchius fuscotaeniatus Nothobranchius geminus Nothobranchius guentheri Nothobranchius hassoni Nothobranchius hengstleri Nothobranchius hoermanni Nothobranchius insularis Nothobranchius interruptus Nothobranchius itigiensis Nothobranchius ivanovae Nothobranchius janpapi Nothobranchius jubbi ​Nothobranchius kadleci Nothobranchius kafuensis Nothobranchius kardashevi Nothobranchius kilomberoensis Nothobranchius kirki Nothobranchius korthausae Nothobranchius krammeri Nothobranchius krysanovi Nothobranchius kwalensis Nothobranchius lourensi Nothobranchius lucius Nothobranchius luekei Nothobranchius makondorum Nothobranchius malaissei Nothobranchius matanduensis Nothobranchius melanospilus Nothobranchius microlepis Nothobranchius milvertzi Nothobranchius mkuziensis Nothobranchius moameensis Nothobranchius neumanni Nothobranchius niassa Nothobranchius nikiforovi Nothobranchius nubaensis Nothobranchius occultus Nothobranchius ocellatus Nothobranchius oestergaardi Nothobranchius orthonotus Nothobranchius ottoschmidti Nothobranchius palmqvisti Nothobranchius patrizii Nothobranchius pienaari Nothobranchius polli Nothobranchius rachovii Nothobranchius prognathus Nothobranchius robustus Nothobranchius rosenstocki Nothobranchius rubripinnis Nothobranchius rubroreticulatus Nothobranchius rungwaensis Nothobranchius ruudwildekampi Nothobranchius sagittae Nothobranchius sainthousei Nothobranchius seegersi Nothobranchius serengetiensis Nothobranchius skeltoni Nothobranchius sonjae Nothobranchius steinforti Nothobranchius streltsovi Nothobranchius symoensi Nothobranchius taeniopygus Nothobranchius taiti Nothobranchius torgashevi Nothobranchius ugandensis Nothobranchius usanguensis Nothobranchius venustus Nothobranchius virgatus Nothobranchius vosseleri Nothobranchius wattersi Nothobranchius willerti BIBLIOGRAPHY Peters, W.C.H. 1868a. Einige Mitteilungen über eine neue Untergattung der Fledertiere und über neue Gattungen und Arten von Fischen. Monatsberichte der Akademie der Wissenschaften zu Berlin, Feb. 1868: 145-148. [https://archive.org/stream/monatsberichted13berlgoog#page/n155/mode/1up] [Nothobranchius: Sys/as new genus] Peters, W.C.H. 1868b. Naturwissenschaftliche Reise nach Mossambique, auf Befehl seiner Majestät des Königs Friedrich Wilhelm IV, 1842 bis 1848, ausgeführt von Wilhelm C.H. Peters. Zoologie IV. Flussfische. D. Reimer Verlag, Berlin: 116 pp., 20 pls. [Nothobranchius: @genus/Mor/Sys][orthonotus N.: in Nothobranchius] Garman, S.W. 1895. The Cyprinodonts. Memoirs of the Museum of Comparative Zoology, 19 (1): 1-179, 12 pls. [http://www.biodiversitylibrary.org/page/12689489#page/9/mode/1up] [Nothobranchius: Sys/family-group name] Roloff, E. 1959. Collecting and Breeding the Nothobranchius species. Tropical Fish Hobbyist (T.F.H.), 7 (10): 12-19, 7 figs. [Nothobranchius: Eco/Aquar] Turner, B.J. 1964a. An Introduction to the Fishes of the Genus Nothobranchius, Part I. African Wild Life (Afr. Wild Life), 18 (2): 117-124, 4 figs. [Nothobranchius: Sys/Dis] Turner, B.J. 1964b. An Introduction to the Fishes of the Genus Nothobranchius, Part II. How and when to collect Specimens. African Wild Life (Afr. Wild Life), 18 (3): 205- 210, fig. [Nothobranchius: Coll/Eco] Wildekamp, R.H. 2004. A World of Killies. Atlas of the Oviparous Cyprinodontiform Fishes of the World. Vol. 4. Amer. Killifish Assoc. Publ.: 368 pp, figs. [Adiniops: Sys/valid subgen. Nothobranchius][Nothobranchius: Rev] Huber, J.H. 2005c. A Review of Family-group names for oviparous Cyprinodontiformes (Pisces; Teleostei). British Killifish Association Publication, Separatum, (October): 16 pp., 1 tab. [Nothobranchius: Sys/family-group] Watters, B.R. 2009. The Ecology and Distribution of Nothobranchius species. Journal of the American Killifish Association (J. Amer. Killifish Assoc., JAKA), 42: 37-76, figs. [Nothobranchius: Rev/Eco/Emb/Age] Nagy, B. 2011a. Auf der Suche nach Nothobranchius in der «Perle» Afrikas. D.K.G. (Deutsche Killifisch Gemeinschaft) Journal, 43 (2): 25-41, figs. [Nothobranchius: Coll/Eco/Dis Uganda] Wood, T. 2012. Colour Polymorphism Occurrence in the Genus Nothobranchius. Journal of the American Killifish Association (J. Amer. Killifish Assoc., JAKA), 45 (3): 80-88, 12 figs. [Nothobranchius: Pat] Watters, B.R. 2015. A Classification of Nothobranchius fish Habitats. Journal of the American Killifish Association (J. Amer. Killifish Assoc., JAKA), 47 (4-6) (December 2014): 152-181, 29 figs., 1 tab. [Nothobranchius: Eco] Reichard, M., M. Janac, M. Polacik, R. Blazek & M. Vrtilek. 2017. Community Assembly in Nothobranchius annual fishes: Nested Patterns, environmental Niche and biogeographic History. Ecology and Evolution (Ecol. Evol.), 7 (7) (April): 2294- 2306. [http://onlinelibrary.wiley.com/doi/10.1002/ece3.2851/full] [Nothobranchius: Dis/Eco] Nagy, B. & B.R. Watters. 2021. A Review of the Conservation Status of seasonal Nothobranchius fishes (Teleostei: Cyprinodontiformes), a genus with a high level of Threat, inhabiting ephemeral Wetland Habitats in Africa. Aquatic Conservation: Marine and Freshwater Ecosystems, 18pp., https://doi.org/10.1002/aqc.3741 [Nothobranchius: Eco/Dis] .

The Nothobranchius and their maintenance