My red tail shark is dying!!

He's not eating and starting to lose color.. I'm still new to fish keeping. What should I do?

The fish has whitespot (Ichthyophthirius)

Do a 90% water change and gravel clean the substrate.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

Clean the filter. Wash filter media/ materials in a bucket of tank water and re-use the media. Tip the bucket of dirty water on the garden/ lawn.

Increase aeration/ surface turbulence to maximise the oxygen levels in the tank.

Turn the water temperature up to 30C (86F) and keep it there for 2 weeks. Then reduce the temperature to 24C. The heat will kill off the whitespot parasites.

Thank you..

Keep in mind that ich is induced by stress so while one can treat for ich more importantly are what are the circumstances that led to it.
How bigs your tank?
What are your nitrates?
Whats the GH of your water?
What other fish are in the tank?
All the above can be potential stressors for fish when out of whack stress leads to disease.

I agree with Utah fish

You can usually find your GH on your local water providers website