TROPICAL FISH ORIGINS: PART 1 – SOUTH AMERICA

Welcome to the first of a 4-part series of articles that seeks to describe each of the four main continental areas within which the majority of tropical fish have evolved. Understanding these tropical origins provides valuable insight into rationalizing the type of aquarium set-up needed for specific species based on the types of conditions that best mimic what time has contributed to the evolution of freshwater fish.

South America

The continent of South America represents one of the most important landmasses in terms of its implication to world climate and atmospheric oxygen levels.

Fresh water is undoubtedly considered a precious resource and South America boasts the world’s majority share. The huge, endless rainforest is of enormous significance, dictating conditions for a vast flora of fresh water life. Think of it as a lung for the entire planet as atmospheric impurities are absorbed and fresh oxygen is released.

The mighty Amazon River basin, encompassing an area in excess of 7,000,000 sq km (2,702,911 sq miles) features the Amazon River, which stretches over 6,000 km (3,728 miles) in length. The scores of tributaries, which drain into the Amazon, cover an area that is approximately one third of the continental landmass.

Consequently, within such a huge area, water conditions can vary and contrast dramatically. In fact, the rivers that deliver water from the east side of the Andes mountain range are often known as White Water Rivers. The water conditions of these rivers often exhibit somewhat higher pH values along with a greater quantity of suspended particles and are frequently turbid; conversely many rivers do feature exceptionally clear clean water.

Black Water Rivers are those with dark tea-coloured water that is heavily stained by tannins from the vast reservoirs of dissolving organic matter composed mainly of leaves and wood.

Dark water habitats may be found everywhere in the Amazon basin, but the most famous black water river is the Rio Negro in Brazil. Many of these areas are highly influenced by seasonal, rainy periods where huge flood plains are submersed and vast areas of vegetation are exposed to aquatic conditions. This dramatically affects the water chemistry of such rivers. As an example, the Rio Negro often has pH values of below 5.

Certain countries such as Brazil, the home to the heart of the Amazon River, have entered into higher levels of economic and industrial development. Mining, energy resource extraction, livestock farming and forestry development are rapidly destroying forests, animals and rich aquatic fauna, which exist in the Amazon River system. This in turn threatens the very survival of life on this planet as we know it today. Impacting such a significant percentage of the world’s limited freshwater supplies is, to say the least, very, very risky and will result in negative consequences for all.

The Amazon River system and the many associated bodies of water found in Brazil, Colombia, Venezuela, the Guyana and Peru are home to numerous species of fish and plants, which are commonly found in millions of aquariums across the globe. In general, conditions consist of soft, acidic water with 25°C (73°F) to 30°C (85°F), depending on the season and location. The atmosphere is generally high in humidity and air temperature.

In summary, many South American species of tropical fish come from tea-coloured water, low plant presence, and warm and acidic water conditions. To ensure you plan accurately for new fish, review the conditions within which they have evolved, keep those parameters in line, and boost positive fishkeeping experiences!