What is the Difference Between Freshwater and Marine Water Animals?

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The main difference between freshwater and marine water animals lies in their adaptations to the specific salinity levels of their habitats. This includes differences in how they regulate water and salt content in their bodies, as well as differences in the types of predators, prey, and environmental challenges they face. Some key differences between freshwater and marine water animals include:

  • Habitat: Freshwater animals live in freshwater ecosystems such as ponds, rivers, and lakes, while marine animals live in marine ecosystems including seas and oceans.
  • Osmoregulation: Freshwater animals have adaptations to prevent ion loss, whereas marine water animals are adapted to prevent water loss. Freshwater fish retain more salt in their bodies than in the water, allowing them to survive in waters with less than 0.05 percent salinity. Saltwater fish, on the other hand, lose water to their surroundings through the process of osmosis and need to drink lots of salty water to maintain a healthy body.
  • Physiology: The physiological mechanisms of freshwater and marine fish are different, with freshwater fish maintaining the ability to concentrate salts within their bodies, while marine fish have evolved mechanisms to replace water lost through osmosis to the seawater and to remove excess salt.
  • Species: There are different varieties of freshwater and marine species. Freshwater fish can be cold water or tropical varieties, while marine fish are all cold-water fish.
  • Care: Freshwater fish are generally easier to keep alive in an aquarium because they can adapt to changes in water conditions, while marine life is more sensitive and requires more specific conditions to thrive.

Comparative Table: Freshwater vs Marine Water Animals

Freshwater and marine water animals have adapted to live in their respective aquatic ecosystems, and while both are adapted to live in water, there are differences between them. Here is a table highlighting the differences between freshwater and marine water animals:

Feature Freshwater Animals Marine Water Animals
Habitat Freshwater ecosystems, such as ponds, rivers, and lakes Marine ecosystems, including seas and oceans
Osmoregulation Retain more salt in their bodies than in the water, enabling them to survive in waters with less than 0.05% salinity Lose water to their surroundings through osmosis, needing to drink lots of salty water to maintain a healthy body
Examples of Species Cold water species like pike, trout, shiner, and goldfish; tropical freshwater species like pacu, golden barb, red-tailed red eye puffer, catfish, guppy, and angelfish Cold-water marine species like seahorses, eels, jellyfish, clown fish, sharks, common dolphin, and tuna

Freshwater animals typically live in habitats with less than 1% salt, such as ponds, lakes, streams, and rivers, while marine animals live in habitats with more salt, like seas and oceans. The different osmoregulation processes in freshwater and marine animals have led to their adaptation to their respective environments.