Austrolebias elongatus

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This fish is quite a handful. Among Austrolebias, it grows to the largest sizes in my opinion. Populations also seem to differ in the sizes which adults reach, with the “Vivorata” population from Argentina becoming largest (as far as I know of course). Different populations I keep can be distinguished on the basis of the pattern of blotches in females and by the colour and the presence of spots in males. I have had an albino male once, but did not manage to mate and breed it. Siamese twins occur relatively often among the alevins.
Austrolebias elongatus is a strong fish, but it suffers in warm weather. The alevins can devour their sibs, if there is a lot of growth variation in a group. This can kill the cannibal, when their brother or sister gets stuck in their mouth.
I keep a pair in a 70 liter tank or an even larger one. Juvenile groups are of five individuals in a 30 liter tank. The populations I keep since about 2005 are “Vivorata”, “Ezeiza”, and “Villa Soriano” (Uruguay).
Eggs are stored for long at 22 degrees C, in relatively wet peat. I often hatch embryos which are about two years old. The fish like eating earthworms. Five liter jerrycans are perfect-size containers for spawning.

Waiting for warmer nights

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I’ve raised a bunch of fry which I want to transfer to the garden. My plan was to do this in April, but night temperatures are hardly rising above five degrees Celsius. My impression in previous years was that fry and juveniles are not as “good” in dealing with cold temperatures as adults.
So I’m waiting….waiting…for warmer nights.
Meanwhile the fry are growing happily.

Austrolebias gymnoventris

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This is an adorable species, for the colours of the males and as it is one of the less common Austrolebias which have appeared in European shows for many years. The females can look extremely healthy, and come with bars or spots. I first bred this species in 1999, and fished it in Uruguay with Heber Salvia in Salamanca, Velasquez and Castillos in 2004 and 2008. The fry are large for the size of the adults, and eat a lot. Newly hatched alevins dive into the peat, making it a bit more difficult to recover them. Females wither easily, and should be fed well. Then they can live for many months, and sometimes over a year while still reproducing. Feeding Tubifex is important to keep them fat. I keep A. gymnoventris in small groups of 2-3 adult males and 3 females in 30/40 liter tanks. This species is known to dislike warm conditions. So tanks should be put in the shade.

Food and transport

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When I return home with a batch of pond food, I bag everything in small breathing bags. This works great, I haven’t observed any mortality so far. Every now and then, I also store red bloodworm and tubifex worms in the fridge in breathing bags.
Afterwards, I wash the bags carefully with tap water and reuse them. More than ten times so far.

Peltier elements

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The incubation of killifish often occurs quite simply on a shelve in the fish room. Then one has limited control over the incubation temperature and thus incubation times can vary. With more constant incubation conditions predictability increases and it becomes easier to decide when to hatch what. This can be achieved by using incubators, but these can consume a lot of electricity. I’ve recently tried some incubators which use Peltier elements. I tried both large models such as the one on the photo and small ones (Herp Nursery II) sold for incubating reptile eggs. I’ve checked the temperatures inside with a datalogger. In a large professional model, the temperature (22 C) was extremely well controlled. In the small ones, I found a temperature gradient from top to bottom. That was no problem, as it remained stable.
Small Peltier incubators consume (if the folder is correct) on average 10W per hour. They can run on 12V DC, meaning it would be feasible to power them by means of a solar panel also.
I use incubators systematically, and after this positive experience, I am replacing incubators by Peltier models whenever possible.

Artemia

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As spring proceeds, it is not always easy to collect pond food with the right size and in the right abundance for all fry. For example, when fishing for food I now need to skim the water surface carefully to get the smallest zooplankton. Contrary to my original plans, I thus decided to raise some Artemia. It is used as a supplement, or as the basic food to raise alevins to a size where I do have zooplankton available in.

To reduce noise and save some energy, I don’t use an aerated and heated bottle anymore. Siberian Artemia ggs harvested from Kulundinskoe Lake are hatched in small containers, in volumes of 500 ml to which I add 15 grams of seasalt. The Artemia hatches gradually at room temperature. When abundant, I separate the husks from the nauplii in a bottle with a valve. The nauplii are tapped and rinsed with tap water (which doesn’t contain chlorine).
This type of Artemia nauplii survives well in the fish tanks, often until the next morning.

Warm water

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I’m in Paris and the weather is great. For Austrolebias, it is important to avoid that the tanks heat up too much. In the past, I experimented with netting, different depths and different tank colours, all with some effects, and it is time to start planning ahead for this year.
Two ideas are under consideration. The first is putting tanks in a mesh tunnel, which provides ventilation and shade. The second idea in the pipeline is to copy a phenomenon which occurs in the field. There the water is often murky due to suspended clay particles. This provides a great experience: when it’s very hot and you step into a pond, at moderate depths your feet will be standing in fresh and cool water! The fish are there as well. So I’m going to buy a block of clay in a craft store and will turn some tanks murky this summer.

Hatching on a sinus (2)

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More on the experiment done in the ECOLAB. The results indicate that hatching does not depend in a simple and obvious manner on the temperature pattern. What the data do suggest is that the proportion of alevins which swim well and which are still alive after two weeks is largest, when water is added at the lowest temperature in the cycle, so that it increases steadily for 12 hours after wetting.

Spring time

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My addiction … I ordered and received banana plants, Musa basjoo and sikkimensis, palm trees Butia capitata, Beccariophoenix madagascariensis, Dypsis decaryi, Rhopalostylis baueri and my currently favourite palm tree Archontophoenix cunninghamiana. Some of them will go in the greenhouse, others in the garden. The bananas are “back-up” for some plants which I had in the garden already, and which might not resprout.
Well, I sometimes germinate palm seeds in an incubator where I keep killfish eggs. Does that count as an explanation?

Hatching bags from Uruguay and Argentina

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I continue hatching annual killifish in small volumes of water at home, feeding the alevins with pond food. This week I wanted to hatch embryos from 9 bags with eggs which I bought on Aquabid, or otherwise. All bags came from Argentina or Uruguay. These bags are usually small and can become completely dry prematurely, killing all embryos in them. To keep the peat inside moist and the air with plenty of humidity, I used to put the bags on a sponge. This was then placed inside a plastic box with a layer of demineralized water on the bottom, keeping the air inside saturated. Disadvantage: the labels fade and bags need an extra waterproof mark. This time I checked the bags weekly and injected a few drops of water if necessary, using a syringe with a needle. This worked fine!
+ The hatching itself went like this: I added very cool water in the morning (14 degrees C), and let the temperature rise in the room during the day (to over 23). The amount of bellysliders was minimal.
Swimming are: A. luteoflammulatus, reicherti, elongatus, cheradophilus, nigripinnis, arachan. The week started well…