It's hard to say without knowing more about your setup.
1. What size tank is the fish in?
2. Is the tank cycled?
3. If so, how long has the tank been cycled?
4. How long have you had the fish?
5. Does it have tankmates?
6. Have you recently tested for ammonia, nitrites or nitrates?
7. What is your water maintenance schedule?
8. Has anything recently changed, such as adding new fish, using a new water conditioner, etc.?
9. What is the tank temperature?
10. Does the fish have any other symptoms, such as lethargy, not eating, etc.?
Also, can you describe the bumps in a little more detail?
sef