Rainbowfish unexpectedly saved by a Czech aquarist
The Best Place for Rainbowfish Enthusiasts
Some of the fish I’ve obtained through my membership in international organizations are not only attractive from a breeding perspective but also come with a breeding history. This history began at the end of the last century, in 1999. A group of Czech aquarists, including myself, set off for a fish exhibition in Antwerp. Along with me were the late Josef Ešpandr; my inseparable and also late friend Josef Brádler; Vladimír Hulman; Josef Chmelař; and Jaroslav Dvořák.
Actually, it began a bit earlier. At the time, the magazine Aquarium Terrarium was advertising the exhibition date. The annual meeting of the International Rainbowfish Society (IRG) took place every year, always on the second weekend of June. Word of our plan to travel to Antwerp reached Gilbert Maebe, the president of the Belgian Rainbowfish Breeders, and Van der Vlist, the then-president of the Dutch Rainbowfish Breeders. I hoped they would invite me. I don’t know if they saw through my subtle hints as I casually informed them, but I received an invitation. However, neither they nor I realized that we were each talking about different dates. Who made the mistake back then, I won’t speculate. We arrived in Antwerp a month after the exhibition.
After driving through the night, we called Gilbert in the morning and found out that the exhibition had taken place a month earlier. He told us that he had some free time in the morning and invited us to visit him. Mechelen was only 20 kilometers away. He gave us the highway exit and said he would wait for us at the Mercedes dealership. That’s how I found myself at probably the best place for rainbowfish enthusiasts in Europe. Visiting Gilbert’s breeding facility was a true experience. In about 50 tanks, countless species of rainbowfish swam, along with some catfish. I took many photos—back then still on film—and my head was swirling with confusion; I couldn’t remember some of the fish names.
Chilatherina sentaniensis
After the photos have been developed, I noticed a fish whose name I didn’t know. I attended an aquaristics congress of Austrian aquarists in Litschau, where Gilbert gave a lecture, and that’s when I learned it was Chilatherina sentaniensis. He told me that he could bring me some young fish if I wrote to him. We agreed that he would bring the fish to the next rainbowfish breeders’ meeting in Lindabrunn the following year. Time passed, and on the way there, I found out that Gilbert couldn’t attend due to a serious family issue. That made me quite sad.
When I arrived at the meeting point, my wife told me that a strange man was calling my name. This man turned out to be one of the best nature photographers and later a friend of mine, Franz Peter Mühlenholz. He informed me that Gilbert had sent the agreed fish. I was overjoyed. That’s how some aquarist friendships work! Gilbert had transported the fish quite far to hand them over to Franz and fulfill our agreement. I took them home to a prepared aquarium.
A few words on breeding and raising these fish: Water parameters are not too critical. A pH above 7, a temperature of 22°C – 26°C (the upper limit for raising them), and hardness up to 10°dH are sufficient. It’s important to note that all rainbowfish species can hybridize both intergenerically and interspecifically, so it is not advisable to take eggs from mixed tanks. It is absolutely necessary to breed these fish in species-pure tanks. Never keep Chilatherina sentaniensis with similar species from the Chilatherina genus. It is impossible to distinguish females of similar species, even if a breeder believes they can. This erroneous confidence has almost led to the downfall of these fish.
Breeding Rainbowfish
Fish can be bred in various ways, and it depends on the breeder which method they choose. I bred them in groups, and after six days, I transferred the fish to an empty aquarium. The eggs hatch in water with a temperature of 26°C after twelve days, just as they were laid. After hatching, they start feeding within two hours. They are very small, about the size of barb fry. The food needs to be very fine. They will eat all types of food, both live and dry, but they prefer surface feeding. Dry food needs to be ground into powder, with a consistency like pudding powder. Such food stays afloat for a while, which suits the fry. Common nauplii of copepods are typically consumed on the fifth day. They also feed on paramecia or the nauplii stage of water fleas from the genus Daphnia. Initially, they grow well, but their growth slightly slows down later. With good care, adult fish reach full size in about a year. Adult fish accept any type of food, preferably from the surface or the water column, but are less likely to feed from the bottom. They thrive best on insect larvae. They can also be fed copepods (Cyclops) and Daphnia. One specific issue is the shorter lifespan of females. That’s why I recommend keeping some females from each spawning in the breeding group.
The Uniqueness of Pure Breeding in the Hands of a Czech Aquarist
Here my story could end. Time passed, and aquarists not only in the Czech Republic but also across many European countries received fish from my breeding efforts. It was 2009, and at the annual meeting of rainbowfish breeders, a great expert on these fish and also my friend, Johannes Graf, gave a lecture on the genus Chilatherina. The lecture covered many species within the genus. When the lecture reached Chilatherina sentaniensis, Johannes reported that no fish had been caught at the only location where this species was found for seven years. This location was a stream that flows into Lake Sentani in New Guinea. In Western Europe, aquarists had crossed this species with similar ones, and the pure form was probably no longer present. A great murmur arose in the hall, and my name was called. I asked my son, who translated what was happening. Martin told me to wait, and we would explain it later. Some aquarists thought I had sold them hybrids. However, Gilbert then stood up and said:
Slavomil received a pure strain from me, and if he hasn’t crossbred them, then you have pure fish.
The tension rose until Johannes, with a smile on his face, announced:
Whoever has fish from Slavomil has the last pure Chilatherina sentaniensis on the planet, and it is necessary to breed them responsibly, or this species will truly go extinct.
I felt a great sense of relief. I had certainty.
At that time, no similar species were probably being bred in the Czech Republic, and nothing similar was swimming in my tanks either. A formula is used to determine the purity of the species based on body measurements and morphological features. The measured results are entered into the formula, and a calculated coefficient is determined, which must have a value of 2.7. Crosses and other similar species have a coefficient over 3.
Thus, what no one planned happened, and I hadn’t wished for something like this either. The sadness over the loss of the fish at this single location was mixed with the joy that the fish from my breeding stock were the foundation for the preservation of this species. A group of aquarists formed to breed this species in its pure form. One of them is my very good friend, the excellent aquarist Zdeněk Dočekal. I would like to ask aquarists, not only rainbowfish breeders, if you have space in your tanks and are willing to participate in this conservation breeding, please do so. You will receive a very rare and beautiful species, along with the joy of helping to save this fish.
My story could end here. But I believe it will continue in the tanks of aquarists. I want to thank everyone who will try.
Sincerely,
Slavomil Boudný
IRG = Internationale Gesellschaft für Regenbogen Fische
