Big black spot

[StrawberryBlonde7]

Am going insane, so far two deep blue chromis have died, with no cause that I could see, today I noticed the yellow watchman as noted in another read has what looks like slime around his gills, now on top of it all the third chromis has a new black spot. Any ideas/ suggestions?
Water parameters are all normal, the fish that I have had, pair of clowns and pair of firefish, and starry Blennie, cleaner shrimp and candy cane shrimp all seem to be in good shape god help me they stay that way. Both sick fish are in separate quarantines

 

[StrawberryBlonde7]

Picture

 

[bigben2057]

Picture

Tank size you seem to have alot of fish. Maybe use instant ocean lifeguard to treat them.

 

[StrawberryBlonde7]

55 gallon they are all very small, the biggest is the mature female clown and she is maybe 2.5 inches, my ammonia is 0 I have a bunch of live rock

 

[bigben2057]

55 gallon they are all very small, the biggest is the mature female clown and she is maybe 2.5 inches, my ammonia is 0 I have a bunch of live rock

Dose it look like ick? (white spots)

 

[StrawberryBlonde7]

No if you can see in the picture central on the fish a darker discoloration

 

[StrawberryBlonde7]

Treating with instant ocean lifeguard not sure how good it isn't they are still alive

 

[crister13]

0 ammonia doesn't really matter if the tank is cycled. It needs to be 0 all the time along with nitrites. What are your nitrates????? And phosphates?

 

[StrawberryBlonde7]

Nitrates are almost non existent, I do a good Walter change every 2 weeks . I have never tested phosphates. I made a hospital tank up the big spot went away treating with lifeguard, one spot of ick, going to go slow hypo