dangers faced fishes
tigers
There were many dangers of the Nile, hippos and crocodiles which are very dangerous.
A "snag" in Huck Finn refers to a submerged tree or branch in a river that poses a danger to passing boats. These snags were obstacles for Huck and Jim as they navigated the Mississippi River on their raft, symbolizing the challenges and dangers they faced on their journey.
Piranas & Anacondas
The same as any other river but including crocodiles.
Families faced starvation, drowning while crossing a river, diseases like cholera, freezing in a snowstorm, mud slides, or ambush by native Americans.
River rapids had to turn back
Heat and possible lack of water.
They must face predators, oil slicks and pollution which can lead to instant death or death by killing the things they eat. They also will face man made materials that may entangle them.
Rhine river
the nile crocodile and especially the nile monitor
Early steamboating faced several dangers, including boiler explosions due to pressure build-up, which could be catastrophic. Additionally, collisions with other vessels or obstacles in the water, such as rocks or snags, posed significant risks. The risk of fire from the wood-burning engines and the lack of effective firefighting measures heightened dangers on board. Lastly, the unpredictability of river currents and weather conditions could lead to capsizing or grounding.