Fresh Water Fish Freshwater fishes are a highly variable group
of aquatic vertebrate animals that spend all, or a critical part
of their life in either inland freshwater or brackish estuaries.
They include all ‘primary’ freshwater fishes such as carps and
cichlids, ‘secondary’ freshwater fishes such as salmon and eels
and some estuarine fish such as archer fish and gobies.
Freshwaters comprise just 1% of the water on Earth. Yet
remarkably, almost half (43%) of the world’s 28,000 fish species
are found in freshwaters, demonstrating high species diversity
relative to the habitats available. The greatest diversity of
freshwater fishes is found in South America, Africa and
Southeast Asia. As freshwater habitats have an increased
potential to become isolated from other water bodies, freshwater
fish endemism is often high, meaning that many species may be
unique to a particular geographic location and found nowhere
else in the world. Chester Zoo’s Aquarium is fairly unique in
that it focuses on freshwater fishes, e