1. Osmoregulation: Oscars are osmoregulators, which means they have the ability to control their internal osmotic balance. When placed in saltwater, the high concentration of salt can disrupt their osmoregulatory processes. The fish will lose water and electrolytes through their gills and skin, leading to dehydration and electrolyte imbalances. This can cause various health problems, including:
- Loss of appetite
- Lethargy
- Weakness
- Bloating
- Skin problems
- Gill damage
- Kidney failure
2. Ion toxicity: The high salt content in saltwater can also lead to ion toxicity in Oscars. Ions such as sodium, chloride, and sulfate can accumulate in the fish's body, disrupting cellular processes and causing damage to tissues and organs. This can result in a range of health problems, including:
- Neurological disorders
- Muscular problems
- Digestive issues
- Reproductive problems
- Reduced immune function
3. Stress: The stress of living in an unsuitable environment can also have a negative impact on oscars. Stress can lead to a weakened immune system, making them more susceptible to diseases. It can also affect their behavior, making them more aggressive or withdrawn. Chronic stress can shorten an oscar's lifespan.
Therefore, it is important to provide oscars with freshwater that has the appropriate water parameters. The ideal salinity range for oscars is 0 to 5 parts per thousand (ppt). If you are planning to keep oscars, it is important to use a water conditioner to remove any harmful chemicals or impurities from the water and to regularly test the water parameters to ensure they are within the optimal range for the fish.