Hoping someone will be able to help me!!

[straw_dog]

I have a fish only 125 gal setup. Been setup since Jan. In Feb I put in a yellow tang, coral beauty, and a couple of clowns. Later added some snails, and crabs and a flying gurnard. Everything was cooking along fine. One day I bought a lemon peel angel and added it to the tank. The tang hated the lemon peel. The tang attacked the lemon peel and the lemon peel ended up in the corner of the tank, eventually they both showed white spots. I treated the tank for ick at that time and had planned to take the lemon peel back but found him dead soon after.
I am not sure what exactly killed the lemon peel. The day he died I saw him swimming very slow across the tank, and the tang was attacking him like he was a piece of seaweed.
Anyway the big problem developed after the lemon peel was gone. Within the next week I lost both clowns, a yellow tail damsel (thought these were supposed to survive anything), and the flying gurnard.
I have no idea what is killing these guys, all the levels look fine.
I do 30% water changes every month and did a couple extra water changes when everything started dying.
The fish are breathing heavily.
The tang, coral beauty, and one damsel are left, along with the inverts.

 

[elfdoctors]

Besides the heavy breathing, have any of your fish had other symptoms, especially more spots?
The timing is very suspicious that the lemon peel brought in a disease, most likely ich. If you had ich in your tank you usually have to assume that all of your fish have ich. Besides spots, heavy breathing is common for ich because it loves to attack the gills.
How did you treat the tang? Hyposalinity and copper are the only reliable treatments. Damsels are tolerant of polluted water (which is what you have during your cycle) but can still catch diseases.
Are your readings okay?
Not many people have flying gurnards. How do you like yours? Based on a little research I did, your tank sounds small for a fish like that (180 minimum recommended). Do you have any pics of him? I don't think I have ever seen one.

 

[straw_dog]

I enjoyed the heck out of the flying gurnard until he died yesterday.

The pictures I have of him aren't that great.

The tank seemed plenty big for him. He would swim up and fly down, he liked it.
I have been treating the ick with some medicine I got from my local shop. I have been using it for about a week and a half now and it looks like its probably not helping.
Doesn't copper stay in your tank and kill everything? What is hyposalinity?
I was noticing the tang has some dark spots by his eyes last night, he also looks dull yellow instead of bright yellow. I came home Friday night around 1am and he was white, the lights were still on.

 

[elfdoctors]

Originally posted by straw_dog
Doesn't copper stay in your tank and kill everything? What is hyposalinity?
Sorry about your flying gurnard.
Copper will permanently bind to any live rock and substrate in your tank. It should only be dosed in a tank without these.
Hyposalinity is a treatment in which the salinity of your tank is lowered to the point that fish can still live but ich will die (as well as corals, live rock and inverts). See the Basic FAQ sticky at the top of this forum for a more complete description of how to do hyposalinity. This is what I did when my tank had ich.