Reflections about the nitrogen cycle...

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Thanks for sharing that with us Avel1896, I read the conversation through and my biggest thought was that we all have to be careful about generalizations we make. The author's comments are definitely stating that he doesn't cycle the tanks and doesn't have to add plants or soil, and I have no reason not to believe his statements. From my personal experience I don't believe this would work with my fish. The areas of interest I didn't get from the reading I managed were what is the source of the water they use when starting a new tank, and what was the source of the leaves, both have the potential of being a source for nitrifying bacteria, as is the Daphnia culture used to feed the fish, he may be indirectly inoculating the tanks with nitrifying bacteria. He also mentions that bacteria in the substrate increases the ammonia during the breaking down of the fish waste and detritus, there may be some truth to that statement.

Overall I would suggest that the method the author uses might work for their specific type of fish rearing but not necessarily work as a general solution. I say this because of a few things:
  1. He is raising Killifish - its life cycle is different than most of the fish other people raise, they have evolved to grow fast, live hard, then die. They live in ephemeral ponds with little water exchange and have adaptations to handle these conditions (this is gleaned from a quick look on the internet I really didn't know anything about these fish until I started looking).
  2. Additionally it seems like some fish species have a higher ammonia tolerance and some killifish seem to fit into this group. See this excerpt Killifish - an overview | ScienceDirect Topics (I would like to read the whole paper but not enough to spend $31.
  3. Many of the tanks he uses are shallow rather than tall, this gives more surface area per volume of water to allow the degassing of ammonia out of the water, I don't know how quickly ammonia will leave the water but it has got to help. The reduction of ammonia via this method would also reduce the generation of the intermediate nitrite.
Overall, the fish are still going to generate ammonia, and this needs to be removed somehow. The most standard way is with the nitrogen cycle, paired water changes, and sometimes plants. It is clear from the thread you posted that there are other ways as well, but they may be a less general solution.

I wonder if this thread should be moved to the controversial ideas thread.
 
Back in the day when I got my first tank, I did an aquarium without cycling it. Within the first week I had lost half my fish, second week I only had one. I didn't know any better back then, so I have proved to myself that Not Cycling = Dead Fish.
Same thing happened to me, when my daughter saved her money, went to Petco (gasp), and came home with a "starter kit", and FISH...advice from the employee there, I will curse eternally, lol...online research, and helpful FREE advice from fish forum members, saved the day...and instilled my love of fishkeeping...and not much later after that, MTS set in...
 
Here is the translation french to english :

I notice on the net that many questions come back periodically on Killi breeding techniques.

Many points seem to cause problems to neophytes, such as water parameters, eggs collection or the artemia nauplia breeding...

Food consists of several things... artemia nauplias for my fry of young and small species (Pseudepiplatys annulatus and Aphyoplatys duboisi).

Daphnia, I live in the country and I finally found generous ponds less than 3 km away. In this period of quarantine and curfew, I also have a pond of 30 m3 (which is used in summer to water the garden) in which I put a good big load of hay, as I occasionally put a few daphnia in it, it allows me to feed in this difficult period. For your information, daphnia can be fished all year round even in winter. They stand at the bottom in winter (or just under the ice layer when it freezes) and on the surface in summer. They live on all levels in intermediate seasons with a preference for areas in the sun.

The main advantage of live food is that it is alive and therefore mobile. A carnivorous or omnivorous fish is naturally tempted to catch it. The predation instinct has beneficial effects on the health of the fish and on their ability to reproduce. In the case of fry, this is even more obvious. They have the natural reflex to catch parameciums or nauplias. It is common for them to ignore powdered food : this is a waste of time and less chance of making perfectly healthy adults.

When I come back from fishing, I store my daphnia in two or three 11-liter buckets...You have to be careful because if there are too many of them, they consume all the oxygen and end up asphyxiating. More or less it is 3 days fedding. I breed about 350 fishes (27 species).

About sensitivity to iron, some biotopes, especially in South America, are quite rich in iron. Obviously killies are not particularly sensitive to iron.

They are especially sensitive to calcium for species coming from biotopes where the water is (very) soft, this results into an influence on growth and development.

It would be nice to talk about the setting of a Killies tank...
Several options are available and they completely differ from the layout of a classic aquarium. One of these options even becomes an obligation when you want to breed annual killies : put a soil to annual Killi tank is doomed to failure.
The first reproach I make to most of the neophyte tanks is that they are too tall, some nano tanks are even totally unsuitable, unless they are only half-filled.

A killie tank must give the priority to the floor area rather than the volume. It is also essential to be able to put a perfectly hermetic lid on it, killies are among the kings of escape and the slightest space left free by is an invitation to escape.
The best thing I found at the moment (apart from making your own tank) are tortoise tanks.

Not all killies need quite the same parameters, but a majority need fresh, slightly acidic water.
There are special cases, but on the whole this is valid for the most commonly encountered species.
The killies that are exceptions to this rule are North American species (Fundulus, Jordanella, Cyprinodon ...) and those around the Mediterranean (Aphanius, Valencia ...).

Two points are important, NO limestone because it hinders the growth and proper development of fish. This has been verified by experimentation on several occasions on fish of the genera Nothobranchius or Aphyosemion.

The overall conductivity (total amount of dissolved minerals) must be quite low because minerals are detrimental to the chorion (egg shell) and interfere with any reproductive effort.

In some small species (Pseudepiplatys annulatus, Aphyoplatys duboisi), chorion cannot withstand a conductivity higher than 100µS. Between 50 and 100µS, a part of the chorion resists. The ideal is therefore not to exceed 50µS if we expect a large progeny. This point has also been verified by experimentation and study of the evolution of the chorion by microscope observation.

So the first point will be to use soft or very soft water for Killies.

Most of the species will like a mix of 80% osmosis water / 20% tap water (even if it depends on tap water). We can soften water by using peat, alder cones or dead leaves (catappa, oak…).
Temperature is quite variable depending on coastal, savannah, and forest species or even high altitude forests. An Aphyosemion australe or Scriptaphyosemion will be comfortable at 26°C while an Aphyosemion mimbon will be comfortable at 18°C.
An important point is to know species area/biotope which you wish to maintain/breed.

For non-annual killies, there are two methods, with or without soil/substrate/sand.

It is possible to make a conventional tank without soil/sand. Many new Killi-lovers find it difficult to set an aquarium without that. Its usefulness will be primarily aesthetic and to accommodate planted plants.
Others, myself being the first, have chosen tanks without soil.
They have several advantages. First of all, it is easy to clean such a tank by siphoning. We can thus remove most of the accumulated faeces and occasionally collect fry. If it does not allow to accommodate usual plants, it is easy to put Anubias and Microsoriums on root or rock. In this case it is easy and quick to remove the entire decor to clean or catch fish. To reinstall everything takes two minutes.
Another advantage, and not the least, this type of tank does not require any nitrogen cycling.

Finally, if the tank accommodates annual killies, soil is definitely not recommended because the killies could lay eggs onto it (Nothobranchius in particular) then eggs will be almost impossible to collect.

For a small species ( - 5 cm) a 10 liter tank is enough for a couple. For a species of 5-6cms 15 liters for a couple, for over lengths you have to go to 20 liters.
This is theory but I prefer think in floor areathan in total volume, that's why I prefer low and wide tanks like tortoises tanks. Moreover Killies do not need a great depth of water.
Apart from this reasoning it is necessary to take into account the behavior according to each species, some almost don't move, others move constantly.

Asked questions :
• these Killis, Aphyo, etc, their biotop is made with soil/sand or leaves litter isn't it ?
• No soil = no planted plants = no cycling ??? Floating plants aren't a game-changer in cycling ?
• Water change every day ?


Answers :
I use lots of leaves but I don't think of it as soil.
Weekly water change of 20 to 30%.
I have never had any nitrite peak and no one I know of who practices without soil has had any with regular maintenance.
On the other hand, I will never run the risk of not cycling a tank with soil. In this case,cycling is necessary because of the large quantities of bacteria that colonize the substrate and contribute to the degradation of organic waste.
Soil in killies biotopes is often made with either fairly fine sand, silt and organic debris (decaying leaves).
My tanks are rather well vegetalized and including an internal air driven sponge filter and no cycling necessary.
I find it hard to consider a handful of dead leaves as soil...First of all because it doesn't have the physical characteristics of soil, plants can't root themselves, and a bacterial colony will not be able to develop as consistently as in a real substrate.
A while ago I checked nitrates nitrites and ammonia on these no-cycled tanks. I confirm that no peaks or even rises occured nor occur. I keep the nitrate level around 10 mg/l.
A friend of mine, a recognized specialist in Nothobranchius, redoes his tanks every month. He removes fishes, collects the spawning substrate, the plants and the air driven sponge filter. Then the tank is entirely washed with warm water, everything is reinstalled and a new spawning substrate. It fills with new water and puts the fish back in without waiting. It has been working this way for more than 20 years without the slightest worry....
 
@Uberhoust I understand what you mean ;) and I do not agree with his "method". It's taking a too big risk to me.
 

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