* Spawning behavior: During spawning season, male goldfish may chase female goldfish in an attempt to mate with them. This behavior is normal and typically harmless, and the white dots may be a sign that the female goldfish is ready to lay eggs.
* Fin rot: Fin rot is a bacterial infection that can affect goldfish, causing their fins to become ragged and white. This infection can be caused by a variety of factors, including poor water quality, stress, and injury.
* Ich (Ichthyophthirius multifiliis): Ich is a parasitic disease that can affect goldfish, causing them to develop small white dots on their bodies and fins. Ich is highly contagious and can spread rapidly through a tank, so it is important to treat it as soon as possible.
* Velvet (Oodinium pillularis): Velvet is another parasitic disease that can affect goldfish, causing them to develop a gold or brown velvety sheen on their bodies and fins. Velvet is also highly contagious and can spread rapidly through a tank, so it is important to treat it as soon as possible.
If you are not sure what is causing your male goldfish to chase female goldfish and have white dots, it is best to consult with a veterinarian or experienced aquarist for further diagnosis and treatment.