Although it must the best known river for us aquarists, there are two different reactions after visiting the world's most water-rich river: absolute fascination or complete disappointment!
Why is this?
Amazonia is home to over 400 mammal species, around 1300 bird species and over 3000 fish species. Most visitors to the region are used to zoos, where there are jaguar to the left and anaconda to the right. But they don't get to see either of these animals during their 14-day visit to Amazonia! Instead, they take a boat up or down the river and see green plant walls 12 hours a day as they pass by. If they're lucky, they'll spot flying parrots or a pig drinking. Frustration is inevitable! We aquarium and terrarium enthusiasts have a different attitude. As soon as the boat stops, we are in the water looking for fish. While fear of piranhas makes the tourists avoid the water like the devil avoids holy water, we are happy about every single piranha we discover. If a tarantula or a snake crawls somewhere, we pull out the camera, while the tourists set new speed records as they run away. We are just a bit special. But that's exactly why a visit to Amazonia is worthwhile for us!
The Amazon's properties
A real shortcoming, however, is the visibility in the Amazon itself. Unlike the Rio Negro, which carries blackwater, the Amazon has whitewater because it rises in the Andes and carries minerals. The minerals give its water 2 ° carbonate hardness and about 1 ° general hardness with pH values around 6.5. Unfortunately, this whitewater is really unsuitable for snorkelling and fish watching. Visibility is a maximum of 50 cm. The blackwater of the Rio Negro, which meets the section of the Amazon near Manaus called Solimoes by Brazilians, is much better suited and offers much better underwater visibility despite its coffee colour. In Novo Airao, about a day's boat ride northeast of Manaus, the famous river dolphins are fed by the natives and have thus lost their shyness towards humans. It was an incredible experience to snorkel in the water with the dolphins swimming free. Although their eyes are severely degenerated, they can still very accurately accept fish from your hand above the water's surface! The water of the Rio Negro, where most of our cardinal tetras come from, is very special: it has neither general nor carbonate hardness and a pH value of 4.5-5.0! Near Manaus, the Rio Negro and the Solimoes join into the Amazon. The differences between the two types of water are enough that they do not mix over a length of 15 km and show a clearly visible dividing line at the water surface.
The 1.8 million city of Manaus, about the size of Hamburg, is usually the starting point of tourist trips to the Amazon. From there, you live on a typical "Amazon boat" and travel up the Rio Negro or around on the Solimoes. These kinds of trips are not really suitable for us aquarists. We should rather form a group, charter a boat exclusively and tell the skipper what we want. Then he takes us to the floodplains with cardinal tetras, to clear tributaries, the Amazon dolphins and the giant water lilies Victoria amazonica. We can then jump into the water wherever we want and pursue our interests. The Victoria amazonica water lily leaves, for example, are very spiny from underneath to prevent herbivorous fish like the pacus from eating them. The issue of mosquitoes is also quite exciting: in whitewater river areas they are murderous and come at you in swarms. In blackwater regions it is much more pleasant and you can even sit on deck at dusk and enjoy the sunset without the bloodsuckers biting you! Blackwater is so hostile to life that not even mosquito larvae survive there. We dragged a fine plankton net along in the water for ONE hour during the boat trip and had exactly TWO small plankton crustaceans (copepods) in it!
Suitable places to go for aquarists
The worthwhile destinations for us aquarists are the small tributaries of the Amazon or Rio Negro. There we find few turbidities and, a little upstream, often relatively clear water. Then snorkelling is also worthwhile, even if we should not expect to find water of swimming pool quality. Testing the water is always an eye-opener: we find the same fish species in rivers that are not so far apart, but which nevertheless have very different water values! Yet in our books and on the internet it often says: Live in acidic and soft waters. You have to experience something like that for yourself...
Dangers in the Amazon
The greatest danger certainly comes from ourselves. We can get lost, get stuck on wood underwater and fall seriously ill far from civilisation. But when we tell our friends about snorkelling in the Amazon, all the horror stories come to light, from the piranhas to the anacondas to the crocodiles! A short info on this: Piranhas leave us alone, but I don't know whether they would become pushy if we were bleeding. That remains to be tested. With sharks, human blood has no attraction whatsoever! Coming across an anaconda is not bad luck, but would be an absolute stroke of luck! You can watch it in peace and it is peaceful as long as you don't hold it. Crocodiles: In Amazonia, among the caiman species living there, there is only one, the black caiman, which can be dangerous to humans. This is why it has been systematically persecuted and almost exterminated. All other caiman species are completely harmless and we can swim peacefully together with them in the water.
Rather book a Rio Negro "cruise" than a pure Amazon tour. You will get much more out of it! The best time to travel to the region around Manaus is July-November with the lowest rainfall, but also the highest temperatures. Immediately after the rainy season, starting in May, the water levels of the rivers are sometimes 8 m above normal and the skippers have difficulties following the course of the river, as only the tops of the trees stick out. This means that a lot of valuable time is lost. Manaus is ideal as a base for the Amazon region and also worth a day or two to visit the famous opera house and the fish market. If you don't want to go up AND down the Rio Negro, you can fly upstream from Manaus to Barcelos and save yourself a boat trip. There are some vaccination recommendations from the tropical institutes that should also be taken seriously. Sometimes tourists are not allowed into the country WITHOUT proof of a yellow fever vaccination. And CAUTION when leaving the country: Do not take any organic material with you!!! The IBAMA (Brazilian environmental authority) already fines tourists heavily for taking leaves they’ve collected home with them. Fish, invertebrates and plants are an absolute NO-GO! Long-haul flights to Manaus are almost always via a larger Brazilian city like Sao Paulo or Rio de Janeiro. Prices were well below €900 before the Corona crisis.
Info on the results and a lot of photos can be found here: Wyprawa badawcza Brazylia