My observations & methods for the maintenance and breeding of Nothobranchius

My observations & methods for the maintenance and breeding of Nothobranchius

Having kept and bred most of the species of Nothobranchius since 1982, I have seen and heard many of the ideas in the way Nothobranchius should be kept. Applying some of these observations to my own methods of maintenance helped me to reach a position where I could keep and successfully breed any of the species without any difficulty, but there were many failures along the way. By passing on some of these observations I will try to identify some of the problems I experienced (and perhaps you are currently experiencing) and how I resolved them. The resolutions worked very well for me but may not for you so you should only consider changing in those areas where you are struggling. If you are happy with the results and the number of fry you are able to produce then don’t change anything. ‘If it is not broken don’t fix it,’ as the old saying goes.

Nothobranchius are quite easy to maintain, and if kept at an average temperature of 24°C and a slightly alkaline pH there shouldn’t be any problems. At a higher temperature the fish will grow rapidly but their lifespan will be reduced, too cool and although they will live a little longer but may not be as productive. Nothobranchius have a healthy appetite, so good filtration to combat the danger of high ammonia and nitrite combined that with regular water changes to ensure that high nitrate and phosphate levels are kept in check. It is worth noting that in soft water areas you may also need to raise the general hardness to ensure a stable pH and avoid what is generally termed a pH crash.

Foods

A wide range of foods can be offered, some willingly take prepared foods others need a little patience and perseverance. In the wild the main diet is insect larvae and water crustaceans, or even other fish. In the aquarium the usual foods offered are frozen bloodworm, cyclops and black mosquito larvae, these are considered the best. Supplement these with live daphnia, white worm and clean live tubifex worms. Take care on the source of the daphnia and tubifex as this is where you can introduce parasites and other predators, usually oodinium, hydra, dragonfly and beetle larvae. Try to find a source of water which does not contain fish, the most common of these in the UK is ponds in the fields for the watering of farm livestock. Always ask the farmers permission, once they know what you are up to they are usually very helpful and will also point out other locations not visible from the roadside. For the larger fish chopped earthworm and beef heart are also relished. With newly hatched fry the majority can take freshly hatched Brine Shrimp nauplii immediately. By the second week you can supplement the Brine Shrimp nauplii with grindalworm, sieved daphnia and cyclops. With some of the smaller species of fish the fry usually need to be fed at first with infusoria and other micro organisms like paramecium and then after the first week the fry can then be introduced to newly hatched Brine Shrimp nauplii.

Peat preparation

Preparing the peat properly for the use as a spawning medium is very important. Do make sure that the peat you purchase does not contain any additives. Peat in its raw state is very acidic and needs to be neutralized as much as possible, especially if you live in a soft water area, as this will cause the pH to crash which may result in the loss of the fish. Fill the bucket 25% with peat then top up with boiling water and allow it to stand for a week. After two days any floating lumps can be squeezed and broken up and any woody bits can be netted off. Once the peat is saturated and sunk to the bottom, gently tip away the water and refill using hot tap water. Allow to stand for about an hour and then drain off the water and dust refilling immediately with hot water. Repeat this process many times for a week. It is very important to remove as much of the dust as possible, otherwise it may dry out too much when storing the peat containing the eggs causing the death of the incubating embryo through lack of moisture.

Breeding

Male Nothobranchius can be extremely territorial. When kept as a group the dominant males will fight for the most suitable spawning site, this can usually be seen when rearing a group of young fish together. Most hobbyists purchase a pair or trio of Nothobranchius so they don’t always get to see how aggressive males can be. In the wild a male will hold a territory displaying to the females that come by trying to entice them onto his patch to spawn, if the female is ripe and she likes the look of him she will enter his domain and they continue to spawn until she has exhausted all of her eggs at which time she will swim off to recuperate and produce more eggs ready for the next spawning sessioNothobranchius Meanwhile the male displays once more as if to say next. In the aquarium this is where problems can occur, once the female has exhausted all her eggs there is nowhere for her to go except behind some plant or up into the corner of the aquarium, but the male still wants to spawn and if no other females are available he will seek her out. Because she has no available eggs he can get so agitated that he ends up damaging or killing her.

Nothobranchius kafuensis “Kayuni” in combat ©Hristo Hristov

With some Nothobranchius keeping a group together presents no problems, having three or four females to one male, some java fern in the aquarium for the females to hide behind and a supply of frozen food supplemented with some live food will keep them in good conditioNothobranchius Some need a watchful eye checking to make sure they are not getting too distressed and separating them for a short while if necessary. In the confines of an aquarium some species can only be kept together for a couple of weeks, some for a week, some for a couple of days and some for only an hour or two. Over the years I have found the best way to keep them is to have two or three aquariums for one species. With the aggressive species it is best to have two males in separate aquariums and the females in a third, introducing the females to the male for a few days and then remove the male. After a period of rest and recuperation introduce them to the other male. With some species, i.e. Nothobranchius ocellatus, even the females need to be kept separate, introducing them individually to the male for only an hour or two. If the female is not ripe with eggs the male Nothobranchius can inflict severe damage or even fatalities in a very short time.

There are basically two ways in which Nothobranchius spawn, the most common being the egg ploughers. I call them ploughers because that’s exactly what they do, the male siding up to the female encouraging her to the bottom, then clasping her with his dorsal and anal fin, he presses the rear of their bodies into the peat and she deposits a single egg down her anal fin which she has folded to create a funnel and as they plough into the peat the male fertilises the egg in the same instance. As the pair separate, the turbulence stirs up a cloud of peat which buries the egg. The male continues to court the female repeating the ritual over and over until she has exhausted all of her eggs. It is at this time she swims away and the male starts to court another female if one is available.

For the small and medium sized fish, it is better to alternate between two aquariums. A glass storage jar filled with about 3 cm of peat is a useful way of restricting the peat and eggs from being contaminated with uneaten food and waste, it also simplifies the collection of the eggs. Put the jar of peat in with the male a day or two before introducing the females to him, he will then take his stance over his new spawning patch eagerly awaiting the introduction of the females. After a week remove the male to the second aquarium, take out the container of peat and eggs leaving the females to recuperate and fill with eggs for a week without any harassment from the male. By alternating between two aquariums the fish can have a week spawning and a week conditioning, this method always produced a good number of viable eggs.

With the larger species a short setup in a small aquarium of 10 to 20 litres is better. Cover the base with 2cm of peat and introduce a trio for 1 or 2 days then remove them to their respective homes and introduce a different trio for the same period. This procedure can be repeated over and over to get a good collection eggs. Whilst in the breeding set up it is recommended not to feed the fish as this will reduce the risk of contaminating the peat and eggs with organic waste and uneaten food thus reducing the danger of fungus attacking the eggs. It is then a simple task to siphon out the peat and eggs into a net and squeeze out the water.

Nothobranchius eggersi “Kibiti Utete” Breeding ©Hristo Hristov

The second manner in which Nothobranchius are known to spawn is egg scattering. To date, 2011, there are three species Nothobranchius geminus, Nothobranchius janpapi and Nothobranchius luekei. Instead of the male encouraging the female to the bottom to plough their eggs into the peat, they often spawn at a high level of the aquarium amongst floating plants with the eggs falling through to settle onto the substrate, The male embraces the female above the substrate at all levels of the aquarium to expel the eggs which quickly sink to the bottom. These three species are also known to be good jumpers so a tight fitting lid and some floating plants such as Indian fern are recommended. The males do not hold a territory as do other Nothobranchius but will chase other males away from the area. Although they do seek out a suitable substrate over which to scatter the eggs, they will scatter the eggs anywhere and the use of a container is a little hit and miss. Because of the indiscriminate scattering of the eggs the best way to collect them is to use a small aquarium 30 x 20 x 20 cm and to cover the base with 2 or 3 mm of peat, then introduce a pair or trio for two days. Remove them back to their separate aquariums for a good feed and conditioning, adding a different trio into the spawning setup. By alternating between two or three trios you will get a good number of eggs on a weekly basis. Collection and storage of the peat containing the eggs is exactly the same as with other Nothobranchius with the incubation period being between 6 and 12 weeks.

The difficulty with these three smaller species is not the maintaining of them or the number of eggs they produce. On hatching the fry are very small, and unlike other Nothobranchius they also remain close to the water surface and this is where difficulty lies with the raising of the fry. It is essential for the first 7 to 10 days to feed the fry with infusoria or paramecium, also as the fry tend to remain near the surface a very slight movement of the water is required to keep the microscopic food circulating towards the surface, this is done with the use of an airline weighted at the bottom creating a gentle rising current. The use of a small pygmy light placed overhead also attracts the microscopic food towards the light i.e. the surface. Once the fry are able to consume newly hatched Brine Shrimp nauplii growth is rapid and are usually sexable at 4 to 6 weeks of age.

Incubation

The speed of development is not equal for all of the embryos. Some will develop through into diapause 1 and then remain resting before further development into diapause 2. Some will quickly develop through and rest in diapause 2, and some will continue right through to diapause 3. A small percentage of the eggs will remain clear and dormant and not until the start of the next rainy season will they then begin to develop through to the various stages of diapause.

Figure 1: First cells just forming, next to the yolk © J.Van Der Zee 1980

Figure 1: A newly laid egg, the first cell(s) have just formed next to the yolk. At this stage the yolk contains many small oil drops that later combine into 1 large drop.  When you see so many small droplets you know the egg is still very young. The 1st cell starts to divide into 2, 4, 8, 16 etc. and the cells become smaller and smaller. At a certain moment, appr. 256 or 512 cells, all cells start to move over the yolk in the direction of the other side. They all stay in one layer due to a process that is called contact inhibition. They avoid each other.

Figure 2: Egg is entirely filled with undifferentiated cells:Diapause 1 © J.Van Der Zee 1980
Figure 2: Here the migration over the yolk is finished and the cells are equally divided all over the yolk due to contact inhibition. They are now so small you can hardly distinguish the individual cells. In the photograph each dark grey spot with a light circle in it is a cell. The development can  stop at this stage and is caused diapause 1. As the egg develops further the cells start to differentiate and they eventually form the embryo.

Figure 2: The embryo forms a much more differentiated structure as a line across the egg This can form a second resting stage: diapause 2. The embryo can hold out in a resting state for a considerable length of time as long as there is sufficient moisture and oxygen available.

Figure 3: Diapause 2 Resting state ©J.Van Der Zee 1980

On the arrival of the rainy season and the wetting of the eggs, most of the embryos rush through to becoming a fully developed embryo in diapause 3 (Figure 4).

Figure 4: Diapause 3 Fully developed Embryo ©J.Van Der Zee 1980

In this diapause the embryo cannot sustain itself for long as it now using the last remains of the egg yolk and the heart is beating to circulate the blood. If the peat is a little  too damp the embryo will hatch into the peat and die. If they remain unhatched the embryo will eventually die from exhaustion and the lack of food. If the conditions are right and there is sufficient water most will then hatch. Some will hold back from hatching just in case it was a false start to the rainy season and will hold out for more water to arrive.

Nature has compensated in this way to allow for inconsistent weather conditions, the strategy being that with early rainfall the fish have some representatives ready to hatch or to progress through to diapause 3 and then hatch, and the opposite being too little or late rainfall they still have embryos ready to develop further before hatching.

Influences on the incubation period

The incubations times usually stated for each of the different species should only be used as a guide. There are many small factors that can have an influence on the development of the embryo through the different stages of diapause. Temperature in the aquarium in which the eggs are laid, if it is too high this may speed up the development of the embryo, too cool and it will slow it down. A temperature of 24°C is considered ideal. It is the same when the eggs are in storage too warm speeds up development and too cool slows it down.

Quality of the water in which the eggs are laid can also have an effect. It is best to try and maintain pH of 7.2 to 7.6, and a medium hardness with a GH between 7 and 10 is good. A GH above 10 is not a problem but is unnecessary. A GH of lower than 7 may result in the pH slowly dropping to a point where it may crash. The amount of pollutants in the water can reduce the amount of oxygen available causing anaerobic conditions and this can add a considerable amount of time to the incubation period. This is easily kept in check by a regular weekly water changes and will keep the water conditions sweet and stable.

It is also known that the females produce pheromone like agents into the water, and if the eggs are left too long in this water it will result in a slowing down of the development through the various stages of diapause. Again this is easily remedied by regular weekly water changes. If the peat contains a lot of uneaten food and waste, bacteria can multiply to an extent where they may consume all the available oxygen whilst in storage leaving the embryos to suffocate and die or attack and consume the eggs anyway. A common problem beginners have is with the storage of the peat and eggs. Every hobbyist is different in the method which they apply to collecting the eggs and removing the water. Finding the correct consistency to achieve can take a bit of practice, too much moisture in the peat can cause the speeding up of the embryo passing through diapause 1 and 2 and because it is so damp they think that the rain is due and move through to diapause 3 and if the eggs are left too long they will hatch out in the peat whilst they are in storage, so when the time comes to wet the eggs the results are either no fry or very few. I have found the easiest way to dry the peat is to pour the contents of the container or siphon out the peat in which the fish have laid their eggs into a 25cm net, then with your hand squeeze all the water out as hard as you can until you can not get another drop out of it. Seeing this for the first time the hobbyist is usually quite concerned about damaging the eggs, but don’t worry as long as it is soft peat you will not crush any of the eggs. I would then spread the peat out in the centre page of a newspaper, fold over the other half and place a small aquarium on top of this for about an hour this will absorb any excess moisture. Then pour the contents into a fish bag about 12cm wide, loosen up the peat either by hand or a little shake and tie the bag up as you would for live fish. Don’t forget to put the name of the species and the collecting date on the bag. This method allows a lot of oxygen to be in contact with the eggs containing the developing embryo which may result in the incubation time being reduced. Some breeders prefer to store the eggs in a flat bag, but in this way you are limiting the amount of oxygen available to the developing embryo and the incubation period may be lengthened. A good indicator that the peat is too damp is a lot of condensation on the inside of the bag.

The embryo does require a small amount moisture in order for it to develop, but if the peat is too dry the embryo may die in the egg resulting in no fry, or not develop properly and usually contains a high number of belly sliders, this can be seen when the peat turns a light fawn colour or dry patches in the bag. Some of the eggs will remain undeveloped and not go through any stages of diapause until the next rainy season, so by wetting the peat you may get a few very weak fry that may survive, and then repeat the process of drying the peat containing the undeveloped eggs which will then start to develop through the various stages of diapause awaiting the next rainy season.

To summarise, any of the individual variations on their own will not make a significant difference to the incubation time of the eggs, but when two or more occur these can add up to make a considerable difference on the plus or minus on the time difference for incubation.

Timing

This is an area some hobbyists beginning with Nothobranchius can have a little trouble with. It is all down to timing. Before the average due date for wetting the eggs it is best to start checking on the progress of the developing embryos a few weeks before. What we are looking for is to see if the eyes are visible within any of the eggs. You will often hear the phrase ‘wait until the eggs are eyed up’. If a few of the eggs are visibly eyed up and the majority are dark in colour, retie the bag and place at a higher level of the fish room, this will raise the temperature by a few degrees and encourage the embryo to develop from diapause 2 to diapause 3. In diapause 3 the embryo is fully developed and is just waiting for the water to arrive, it must not be left for too long at this stage otherwise it may die from starvation. If all the procedures for the incubation of the eggs were correct they will be ready to hatch at the stated average storage time. It only takes a little practice in this procedure to establish your own incubation times.

Wetting the eggs

Now the eggs are ready for wetting. Again you will hear of many opinions on how to do this. It was in 1981 when I started to keep and try to breed Nothobranchius. The breeder showed his methods and I have never digressed from this because it worked very well for me. Last thing at night before turning out the main lights of the fish room, I would empty the contents into a small aquarium 30 x 20 x 20 cm, I took some mature water out of some existing aquariums and then add about 25% of cold tap water to this. Pour this onto the peat to a depth of about 30 or 40 mm then leave to stand overnight.

If the timing was correct the next morning on examination of the aquarium, there you will see lots of fry just above the peat level. Immediately introduce the appropriate food feeding little and often. The next day I would add another 2 cm of mature water taken from an established aquarium and by then there are usually more fry which have since hatched out. From day three I would start to add fresh tap water adjusted to the right temperature and continue this procedure daily adding the water to the front of the aquarium which creates a space clear of peat. It will become evident that this space is required because by adding newly hatched Brine Shrimp nauplii to the rear of the aquarium it will make its way forward towards the light and any uneaten nauplii will die in this area making it easy to siphon out with the use of a length of airline, also check to make sure that none of the fry have been siphoned out with the waste before discarding it, as this area is also where the fry will congregate to feed. After a week all the eggs which were ready have hatched and the fry are now large enough to be carefully netted or siphoned out to a larger bare rearing tank in which the rapidly growing fry can be easily maintained. If you have a good number of fry then it is your choice to either discard the peat containing any undeveloped eggs or to re dry it for further incubation to obtain some more fry at a later date. Personally I always discarded it to the garden as it now contains a lot of organic waste and can easily turn rancid.

Finally, do keep your own records of incubation periods for comparison, many times in the past have I followed another hobbyist strict instructions and for it to end in failure. In theory you can be doing everything right but you are not getting the results and only by a visit from an experienced breeder can the minor problem be brought to light. So persevere and don’t be afraid to ask.

Good Fish keeping, Mick.

Nothobranchius guentheri “Zanzibar” ©Hristo Hristov

 

Nothobranchius for beginners – give them a go

by Mick Agnew (Reprinted from Killi-News 539 Nov/Dec 2010)

At the recent visit to the Killifish conven- tion in September 2010, when enquiring after the Notho keepers I was dismayed to learn that there are not many members keeping them. The other comment I got was ‘I always get velvet when keeping Nothos’. After a few comments to the contrary, I thought I would pass on some useful tips as to their care and breeding, and some precautions I take when pur- chasing fish and eggs. A few times in the past I purchased fish knowing they were infected with velvet, but they were a ‘must have fish’. By following some simple rules I never passed on the infection to the rest of my fish house and was able to clear the fish of their unwanted hosts. Velvet or oodinium is a parasite, which if left unchecked will explode in the aquarium at some stage. There are many good brands of treatments on the market my own par- ticular preference is one by Interpet, Anti slime & velvet cure. I always used this treatment as a precaution even if there was no visible signs of infection on the fish as the free swimming parasites are invisible to the naked eye.

With newly purchased fish I always sepa- rated the sexes so that the females were not harassed by the males allowing them to settle in a much calmer environment. Keep the aquarium dark as this also reduces the reproductive life of the parasite. If you could see the egg cysts on the fish you purchased, which look as though they had been sprinkled with pepper, the fish will need an additional treatment after you have run the full course of treatment for velvet. I would recommend a 50% water change and then start a second course of treatment using an antibacterial agent; my own preference is Myxazin by Water Life Research. The reason for this course of treatment was the parasites usually striped the fish of their natural protective coating leaving them prone to fungus infections. After three weeks you should have nice clean healthy fish ready to breed.

When purchasing eggs, a different strat- egy is required. I would wait until the fry were three weeks of age before treating for velvet. I never found any other treat- ments were necessary.

Do take care that you didn’t contaminate any other aquariums whilst preventative quarantine was taking place. I used these methods for over 30 yrs and never had an outbreak in any of my aquariums.

Most of the Notho’s require a bit of space. Males can be hard drivers, and unless the females have somewhere to hide and rest they will soon become tired and emaciated resulting in their demise. With regards to water conditions, i.e. pH, hardness, tem- perature ect, I never found this a problem. As long as the fish were properly accli- matized to your water conditions. A pH of neutral to slightly alkaline is preferred, a temperature of 24°C to 26°C is ideal. Try to talk to the vendor and find out the water conditions they had been accustomed to and the types of food they had been fed.

Preparing the peat properly is another important process to their well being. As you know peat in its raw state will lower the pH and if you have soft water in your area like I have the pH will crash causing a lot of stress to the fish and even death. You will hear of many opinions as to which is the best to use, personally I haven’t found any difference as to the brand name, but do make sure there aren’t any additives in it. Firstly you need to soak the peat to release the high acid content. Fill the bucket 25% peat then fill with boiling water and allow to stand for about a week. Any floating lumps on the top can be squeezed and broken up, any woody bits can netted off. Once all the peat is saturated and sank to the bottom, gently tip away the water and refill using hot water. Allow to stand for about an hour then drain off the water and dust, repeat this process daily for a week, it is very important to remove most of the dust because otherwise it dries out to much when storing the peat containing the eggs.

Which fish do I start with? There are many I would recommend for beginners, N. foerschi, N. guentheri, N. flammicomantis, N. eggersi to name just a few, all are classed as an easy and productive fish to keep and breed as well as being extremely colourful.

As I have said previously, it is best to house males and females separately. Keeping them apart for about 1 week allows the females to rest and fill with eggs. Putting a male and two or three females together in a breeding setup for one or two days will give as many if not more eggs than keep- ing them together permanently. Whilst in the breeding setup there is no need to feed as they are only in there for a day or two, and this eliminates contamination of the peat that the eggs are deposited in, reduc- ing the chance of bacteria and fungus attacking the eggs. For most fish I always used a jar filled with about 35 to 40mm depth of peat. In this the male would dis- play, encouraging the females to come in and lay their eggs.

After a couple of days I returned the fish to their respective aquariums for a good feed and rest. The peat containing the eggs I would pour into a 10″ net and squeeze hard until no more drops of water were expelled. Then spread the peat in the mid- dle pages of a newspaper and leave for no more than one hour. Empty the peat into a 5″ or 6″ fish bag and loosen up the peat. At the same time look for the eggs so that later you are familiar with the size and number of them. Tie the bag as you would for fish and don’t forget to write the date of collection and the name of the fish and store them at a temperature between 20°C and 30°C. How long to store them depends on the temperature of the water they were laid in and the room temperature they are stored at. How dry should the peat be? You will often get the reply of about the consistency of pipe tobacco which means nothing to a non-smoker. In general, the peat should be dark brown. If when stored the peat is black and you get a lot of con- densation inside the bag, the peat is usually too wet and the eggs will hatch in the peat. You can still get viable fry but they need checking much earlier. If the peat is too dry and is fawn coloured, the embryos will die in the egg through lack of moisture. It takes a bit of practice but you will get there. In general for the fish named above it is about 5 to 8 weeks. I always start checking them at about 4 weeks to see if the eggs have started to eye up, you can see this by the appearance of two bright spots in the eggs these are the eyes.

When a good number of the eggs are show- ing the eye spots they are ready to hatch and just waiting for the rain. Wetting the eggs, again you will hear of many prefer- ences on how to do this. I would empty the peat into a small aquarium 30x20x20cm take some water from a mature setup to this I would add about 25% of cold declorinated tap water and pour over the peat to a depth of about 30mm. I always did this last thing at night before turning off the lights. This always worked very well for me and when I looked the next morning most of the eggs had hatched and the fry were near the surface looking for their first food. With all the above named fish they are all able to take newly hatched brine shrimp immediately. Each day I would add a little more mature aquarium water, not chilled, until a depth of about 12cm. Then I would net them out to a bare aquarium setup of the same size with a mature filter installed. Feeding 3 or 4 times a day the fry grow rapidly doubling in size for the first 3 to 4 weeks. Take care to siphon out any uneaten food and add fresh water daily.

At about 4 weeks of age you should be able to see the young males starting to sex out, by this time you should have moved them on to a larger aquarium and there are usually no problems leaving them together. When the young fish are about 6 to 8 weeks old they will be spawning in various locations of the aquarium and it is usually at this time I put in two or three pots for group spawning. It is worth not- ing that this method will produce a great number of eggs.

Nothobranchius are greedy eaters and will take all live foods and most frozen foods. My own preferences are frozen blood- worm, cyclops and black mosquito. They can be trained to eat flake food, when I put spare males in my community aquarium they would see the other fish eating flake and mussel in to take the food. I am very lucky were I live, because most of the fields around the town contain dew ponds or circular concrete ponds for the cattle and sheep to drink from. There are no fish living in these ponds and they are ideal for collecting daphnia and cyclops so I had live food virtually on tap.

It is worth noting that many of the so called easy nothos are often neglected by the more experienced hobbyists who are looking for the newer species and the more challenging fish, and they are often in danger of being lost to the hobby here in the UK, as has happened many times in the past, so by having a go helps maintain the species in the hobby.

I hope this article has given you some inspiration you and will give nothos a go. Do let us know how you get on and I look forward to reading about your experiences and disappointments in future issues of the Killi-News.

Nothobranchius eggersi “Bagamoyo” ©Hristo Hristov

Useful Links

A-Z of Nothobranchius
Mick Agnew – In Memoriam
WildNothos – Bela Nagy
Annual fishes scientific.pdf (requires registration)
Nothobranchius Maintenance Group
Laboratory manual for culturing N. furzeri – Tyrone Genade
Laboratory breeding of the short-lived annual killifish Nothobranchius furzeri
From the bush to the bench: the annual Nothobranchius fishes as a new model system in biology
Nothobranchius furzeri Information Network
AKA – Public Library:Nothobranchius – Brian Watters
Breeding and maintenance of South American annual killifish by Charles Nunziata KilliNews 608 2022
How to breed Nothobranchius killifish – Devin Espinoza. TAKO YouTube
Breeding and Care of Nothobranchius – Tyrone Genade YouTube

References

Developmental biology of annual fishes. I. Stages in the normal development of Austrofundulus myersi Dahl – Journal of Experimental Zoology John P Wourms Nov 1972
The developmental biology of annual fishes. II. Naturally occurring dispersion and reaggregation of blastomeres during the development of annual fish eggs Journal of Experimental Zoology John P. Wourms Nov 1972
The developmental biology of annual fishes. III. Pre-embryonic and embryonic diapause of variable duration in the eggs of annual fishes – Journal of Experimental Zoology John P. Wourms Dec 1972