This website has been down for a number of months. It had been hacked and blocked, but that is all fixed now. Meanwhile much has changed around me. I will resume fieldwork in South-America with colleagues from Chile, Argentina and Uruguay. A first model to predict killifish population dynamics is being debugged. The fish are done with overwintering. See you all soon!

Austrolebias reicherti

Austrolebias reicherti (Paso del Dragon, 2020)

Returning fish to the shed now that cold weather approaches, this trio of Austrolebias reicherti (Paso del Dragon) appears. They are about eight months old. For a while, I had a line from the same location where the males had a more pronounced blue hue. We managed to karyotype one of them and it turned out to be a triploid. Whether that was the cause of the colour difference we observed or not could be answered by karyotyping a bunch of wild-caught fish with colour differences. Karyotyping can be done by fin-clipping and a recapture where the regenerating fin is sampled, no fish would have to be sacrificed for this test.

Vanilla, fish, tea

Kitchen hatching. 2020.

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.


Some boxes with peat on my shelves have been there for years. It is always difficult to know how many eggs are actually in one, and I would like it if all that peat could take up a little less space. So I’ve decided to attack the problem at the root, and “concentrate” a peat before it gets stored. When I collect it from a tank with breeders, it is poured into a round container from which you can pour off the water and particles at the surface easily. That mix goes into a shallow tray, so that any eggs spilled out can be recovered. The mix from the tray is poured over a net, the water added to the bowl again and the procedure repeated. The peat in the net is supposed to be relatively egg-free and can be discarded or dried and re-used. If the peat contains any eggs, they make up an increasing fraction of the peat remaining in the bowl.


On the first of October, a Brazilian newspaper article probably made the hearts of many killifish breeders miss a few beats. The Brazilian federal police, with the support of several institutions, did searches in several places after some 37 parcels with killifish eggs had been seized at five locations where they were sent from. The Federal Police claims to launch 12 police inquiries in the countries of destination of the mail orders (US, Germany, Bulgaria, Malaysia, Hungary, Russia, Ecuador, Czech Republic, China, Great Britain, Argentina and Scotland) to investigate the alleged smuggling and environmental crime. In the searches, several aquariums were found in the homes of some involved, containing hundreds of fish (the system looked really good by the way) and eggs.

These are the facts. Then there are the accusations. An aquarium staff member is accused of “biopirataria” and the recipients of the mail orders are claimed to be researchers and collectors. What that means is unclear. Whether these researchers research anything to do with killifish is unclear. I read this as an incrimination, without evidence that it has anything to add next to the fact that export legislation has not been followed and maintenance permits were not present. It seems destined to reinforce the claim of biopiracy, which is outrageous. I am certain the recipients have no other intentions than to breed and share their killifish further and that there is no transfer of public knowledge into private hands. If the involved researchers produce new knowledge based on their (illegal) material, the benefits will be open to all. That’s how it works. I don’t know of any industry interested in patenting or commercializing killifish species.

What I really dislike is that a killifish breeder and apparently “trader” is almost depicted as a drug producer and trafficker. I don’t want to dispute the relevance of nature protection laws at all but see little benefit in this whole operation next to pointing out that some phenomena are illegal. Illegal does not mean unethical. Disturbing is that there is no mention of what happened to the living material confiscated. Are the fish allowed to complete their life cycles, will the eggs develop and contribute to a next generation? Does their natural environment still exist, since the time when the ancestors of the eggs were captured? How many generations have been bred already by the enthusiast outlaws before these eggs were shared?

In replies and a poll circulating, the discourse is present that killifish have been regularly saved from a single or a few ponds where they occurred before these were destroyed. I propose that when natural habitat is destroyed in a country or destined to be destroyed soon, that from then on anyone can keep and trade the animals specific to that habitat freely. This is a principle, and I am not going to work out the legal consequences. The idea is just that when a state does not take it’s responsibility for a natural population or a species, that we still can if we want to.


Austrolebias gymnoventris Salamanca

After some years without them, I’ve started breeding Austrolebias gymnoventris “Salamanca” again. The pairs I have now have been very prolific. What I like about this species are the dark body colour they can get and the beautiful contrasting spots on their anal fin in particular. They can deal with high temperatures, but the water needs to be clean and with little nitrates.


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.

Straight from the bag

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.