I’ve been slow with most hatching this year, for various reasons. Therefore I need to catch up a bit right now. Often at home, it seemed a good idea to have the alevins right in front of me for a while. So I hatched them on a shelve in between vanilla cuttings and my favourite teas, with rain water. When they are a few days old, most alevins will go to the garden where it cools well at night. There currently are A. elongatus, bellottii, luteoflammulatus, univentripinnis, gymnoventris and wolterstorffi swimming in the kitchen.
An article in a gardening magazine showed a semi-underground greenhouse. I’ve been thinking of keeping killifish without heating year-round often and tried many things, but this might be really something, especially for large numbers of big tanks:
An article with lots of examples is available here: https://insteading.com/blog/underground-greenhouse/
I just got notified of this one on the forum of the Uruguayan Aquarium Society AUDA, which I find a really nice example of a useful DIY filter system. The three stages are easy to separate and modify. Too bad I haven’t got any tanks with filtration myself.
Tonight I hatched two bags that had arrived from Argentina four months ago. At arrival, the eggs were in sealed bags completely filled with peat and sphagnum and with visibly many eggs. If the sealing would hold tight during incubation, there might be a risk that oxygen might lack at some point, while low oxygen is no problem for fresh eggs and can help to store them for longer. I cut off a small corner of each bag and placed them separately within a larger ziploc bag. This seemed the best way to avoid desiccation, while allowing oxygen in. Here’s the result. Two very successful hatches, one of Austrolebias bellotti, the other of Austrolebias elongatus. Both from Ezeiza. PS: They were hatched in 1cm of water and there was one bellyslider. I am planning to cut corners like this more systematically.
While cleaning tanks with fry, I discovered this egg raft, probably from a Chaoborus phantom midge. The mother has emerged in the fish tank, and laid her eggs on the surface.
I don’t know if it is very easy to spot, but on this photograph an egg with a developed embryo. You can see its right eye and it’s an Austrolebias charrua (“Canal Andreoni”) from peat collected in June 2018. Particular about this embryo is that it overwintered without heating, in a box with peat standing next to the cold tanks. It has been at temperatures as low as 4C, maybe even 2C. I will try to convince it to hatch in April, when night temperatures in the garden house rise above 10C.
Things break down. Fortunately, this type of small incubator usually does so in the same way: its Peltier element that cools and heats dies. The repair costs a few euros and takes less than an hour. So by now, the incubator is filled again with eggs of several killifish species and fry in their first week after hatching. As it is springtime, I am germinating chillies in it too.
This is how I grow fish at home during winter. They are hatched in a small Peltier incubator, and kept in there for a few days with Artemia as the main feed.
After that they are transferred to relatively flat boxes with tap water, rain water and java moss. The food then becomes a mix of Artemia, Daphnia, copepods and tubifex or blackworm. Great at that point is that mortality can be almost avoided completely if the tanks are not crowded. You should count an Austrolebias alevin from a small species per 150 square centimeter tank surface. For large species, count two to three times that surface.
At these low densities, the fish will grow to maturity without problem. In the stack: Cynopoecilus melanotaenia (Paso del Dragon), Austrolebias charrua (Canal Andreoni), Austrolebias patriciae (Cruce Ferrocaril), Austrolebias vandenbergi (Talon Cansado), Austrolebias reicherti (Paso del Dragon), Austrolebias luteoflammulatus (Ruta 15km7.5, Canal Andreoni), Austrolebias gymnoventris (Velasquez).
Inside the wooden house, there is still fry approaching maturity. They were born a few weeks ago and have been fed once with Artemia, after that with pond invertebrates. Now they will need to overwinter at relatively small sizes and without heating. Critical to make this work seems to be using tanks with a large surface and low depth and to have sufficient thermal mass in the house. When I see a plastic box in a shop, I get the feeling I can predict how many I can raise in there to maturity, just by looking at the surface area. Maybe it’s time now to start experiments on density-dependent growth and survival in my fish.
In the house I also store orchids (Zygopetalum), palm trees (Archontophoenix) and citrus (Yuzu, finger lime) during winter and cuttings of Physalis Peruvian groundcherry.
A simple trick which seems to work to attract a lot of Culex mosquitos to a tank so that you can feed killifish fry with their larvae developing from the eggs they lay in there, of any age you might need:
Add a small amount of wheat flour and yeast to the (dechlorinated) water of a 80L basin partly shaded. If the mosquitos are around, soon you will even smell how many they are in there. The flour was my idea, the yeast Milan‘s.