Poorly Goldfish Again!

Hi, hope someone can help...my goldfish has been suffering with constipation so he is therefore lethargic...he's bloated and so we are starving him like recommended and giving him fish tonic.

However, ive just noticed that he is only breathing through one gill...he's not breathing fast and doesnt appear to be distressed but he's never had gill problems before...no other signs near his gills that suggest illness. Also, near his back there are really tiny pinprick type black dots..they look like they are underneath his scales...never seen them before as i do look at his scales and tail/fins often to make sure he isnt getting anything like ich or fin rot etc..

im stumped...anyone have any ideas?