What will happen if you put a saltwater fish into freshwater aquarium?

Putting a saltwater fish into a freshwater aquarium can have several adverse effects on the fish's health and survival:

1. Osmotic Imbalance: Saltwater fish are adapted to the high salinity of ocean water. When placed in freshwater, the lower salt concentration causes water to enter their bodies through osmosis. This can disrupt the fish's body fluids and electrolyte balance, leading to internal swelling and organ failure.

2. Ion Regulation: Saltwater fish have specialized mechanisms to maintain proper ion concentrations in their bodies. Freshwater lacks the necessary ions that these fish require, such as sodium, chloride, and magnesium. This disruption in ion regulation can affect various physiological processes, including muscle function, nerve transmission, and enzyme activities.

3. Gill Damage: The gills of saltwater fish are structured to extract oxygen from the high salinity of seawater. In freshwater, the lower salt concentration reduces the efficiency of oxygen uptake. This can lead to respiratory distress and gasping for air at the water's surface.

4. Stress: The sudden change in water chemistry and environment can cause severe stress in saltwater fish. Stress weakens the fish's immune system, making them more susceptible to diseases and parasites that are commonly found in freshwater aquariums.

5. Disease Transmission: Introducing a saltwater fish into a freshwater aquarium can potentially bring diseases or parasites from the ocean environment. These pathogens may not affect the saltwater fish but could pose a significant risk to native freshwater species.

It is important to note that the effects of placing a saltwater fish in freshwater can vary depending on the species' adaptability and tolerance. Some saltwater fish may temporarily survive in freshwater conditions but will eventually succumb to the adverse effects mentioned above.

For the well-being and survival of saltwater fish, it is crucial to keep them in appropriate saltwater aquariums with the necessary water quality parameters, salinity, and environmental conditions.