Angel Not Eating

One of my two angels is not eating and is lethargic.   When he does swim, he swims very slowly.  But mainly he hangs out near a plant at the bottom of the tank.   He hasn't eaten in 3 days although he does come to the top occasionally appearing to look for food but when i add some flakes he doesn't eat and returns to the bottom of the tank.
 
All water parameters are proper.  Water temp is 78.    I do notice lots of   black specs near the top of his body---less than 1mm each---not sure if it's his natural coloring or is something else----I couldn't get a good picture of it to show the specks.
 
All 8 of my other fish appear healthy
 
recent photo before this happpened:
 
 

One problem with feeding flakes is that fish can often gulp air down with the food, sometimes causing swim bladder problems. Is your angel having any buoyancy issues? 

Black specs you say? There is a chance it could be a parasite, get a closer look if possible. If I remember correctly Angel fish do get swim bladder commonly compared to others, perhaps try some peas with him/her?

no bouyancy issues---he stays upright--not swaying side to side----just very listless and not eating at all---other angel is doing fine as are all other fish

from what I've read online, it could be black spot parasidic disease---the med recommended is mardel coppersafe---is this med ok to treat the entire tank of 9 fish including corys, bolivian ram, angels, and a pleco?   is this worth a try?
 
http/www.amazon.com/Mardel-BC464341-Freshwater-CopperSafe/dp/B00025662O/ref=sr_1_2?ie=UTF8&qid=1384214754&sr=8-2&keywords=mardel+coppersafe

I have sea salt---is that ok to use for a dip?

ok---I bought some morton's table salt without iodine---the angel is in 2 litres of water mixed with one drop of ich cure by Mardel and 2 teaspoons of salt--will leave him in for about 10  minutes and then return him to tank---will repeat tonight and tomorrow--hope it helps

I wouldn't add the ich cure, your fish almost certainly does not have ich, plus (correct me if I'm wrong) some meds don't work with salt. The salt alone should be enough, if that's what my fish had. Also, never leave them in for more than 5 minutes at a time, the stress could kill them. Watch the fish closely and take it out immediately if it shows signs of severe distress; use your judgment here. Most fish will freak out, considering they've just been moved into salty water from fresh. Some may even jump.
Any sodium chloride is fine as long as it's just that--no fluoride or iodine, or any other type of additive really. Make sure the salt is completely dissolved in the water and the water is the same pH, temp, etc. as the tank water (preferably use some of the tank's water) before you put in your fish.
Good luck!

i did use tank water---left him in for 15 minutes---didn't seem overly stressed----will repeat tomorrow