Help New additions to tank died

[Fish Keeper82]

I have a 170 gallon with a blue tang, cardinal, and green chromis. This tank has no corals I do have about 200 lbs of live rock,160 lbs of aragonite sand and a 30 gallon sump with skimmer.

I've had the fish for about 7 years and decided to add more. I added 2 more green chromis and about 5 days later they died. I temperature acclimated them and slow dripped also before adding to tank. At first they had a great appetite and looked happy. Second day was same. Then on the third day I noticed some vertical lesions on both of the new chromis. There was no harassing by the tank mates. Any thought why the new fish had these lesions? The following day the lesions looked worse. Then they died the day after.
My tank parameters are ammonia 0, nitrate 20. I don't monitor the ph because of all the live rock and aragonite. But every once in a blue moon I do check it it is spot on.

One thought I had was I did not have a heater in the tank. Temp was and has been 73 degrees ever winter. I have since added two fluval 300 watt heaters and set it to 78 degrees. The tank stays at about 77-77.5 now. What temp is your tank set to?

Is it possible my original fish are somehow hardier now after living through several winters at 73 degrees? IDK
Any thoughts? I'm reluctant to add more fish until I at least have a probable cause of what happened.

 

[Betta132]

Chromis are prone to coming in sick. Now your tank probably has whatever the new fish had.

 

[Fish Keeper82]

Nah this was over two weeks ago all else is fine actually better than before. Fish seem happier now that temp is up

 

[snorvich]

Uronema Marinum

 

[TitanCi]

^thats the first thing that came to my mind

 

[Fish Keeper82]

"Fish with either Brook or Uronema lose color very rapidly, appearing pale and "œwashed out". "
The chromis did not have this loss of collor at all. They were same color with a light vertical pinkish stripe that looked irritated. I went back to fish store and all other chromis in their tank looked healthy. I don't know , sounds like from what I read Uronema was not it.

 

[Betta132]

Could the blue tang have done it?

 

[Fish Keeper82]

Not likely.I watched them really close and unless it was at night( which the tang won't come out of the rockwork at night) its not really likely

 

[todddye]

I suspect your LFS runs copper at less than therapeutic levels which kept the parasite in check while in their tanks. Once you removed the fish from copper, the parasite was able to reproduce rapidly. Do a search for pictures of chromis with uronema and see if the pictures look like what you described.

Unfortunately, this is fairly common with chromis.

 

[Fish Keeper82]

Thanks .yes the description was not accurate but the pictures were close.I believe this was the cause.