Why is one of my Bala sharks is breathing really fast while my other sharks are fine Please help!?

Rapid breathing in one of your Bala sharks could indicate stress, poor water quality, or a potential illness. Check the water parameters, including ammonia, nitrite, nitrate, and pH levels, ensuring they are within safe ranges. Additionally, observe for signs of disease, such as lesions or unusual behavior, and consider isolating the affected fish if necessary. Ensuring a calm environment and maintaining good tank conditions can help improve the situation.