New fish keep dying

[Porpoise Hork]

My current setup is a 40G mixed reef tank that's been up for about 18 months now. All has been good and everyone happy and healthy until I had a mis-hap with a dose of buffer and shot my alk through the roof. I ended up losing my Cherub angel and Six line as a result, all the rest of my tank inhabitants have been OK. I have tried adding new fish to the tank and all seem to do well for a week or two after being introduced but then go from active to dead in a couple of days. So far I have tried and lost a Royal Garamma, Coral Beauty, Fairy Wrasse and bi-color pseudo. Both the coral beauty and pseudo developed a spot on their left flank where it looked like they had rubbed off some scales a few days before they died. It wasn't all at once, I added one a week goes by and all is well then within 2-3 days they were dead. This has happened with all the recent additions.

My tank currently has 2 ocellaris clowns, a red and purple fire fish, long fin cardinal, and LM blenny. These are all fish I added back at the start of the tank and have never had any issues with them. There has been no aggression from any of the current inhabitants to the new additions or vise-versa. So I am at a loss as to what to do. I'll be moving to a 75g in a few weeks so I want to nip this in the bud before the move.

My current water parameters are as follows.
Sal 1.024
PH 8.0
Alk 8.8
Cal 390
Mg 1340
Ammonia 0
Nitrite 0
Nitrates .5
Phos .75
Temp 77.8

Filtration - 306 with 100g Purigen x2 (fresh regen), 11.5 oz. Chemipure Blue x2 (new), 100g Carbon x2 (new) and two trays of Bio-Home Ultimate in place for 1 yr now.

Here is the pseudo about a day before it died. I saw no loss in appetite, or other unusual behavior like rapid breathing or hiding, darting etc. Just one day they looked good, then I saw this spot on them, then dead. None of my existing fish have shown any signs of similar marking or loss of scales.

 

[Tahoe61]

The fish did not succumb to an alkalinity swing but rather a disease process.

Since your changing tanks I would take this time to quarantine all fish. Could be Uronema marinum.

Moved to Fish and Disease Discussion.

 

[HotRocks]

A possibility here...

Your tank has Brook or another parasite present.

https://www.reef2reef.com/threads/brooklynella.247938/

The fish that are currently in the tank have developed an immunity to it, whereas your new additions cannot fight it off.

As @Tahoe61 mentioned, I would highly recommend setting up your new system and moving all coral, rock, etc to the new tank. Allow it to be fallow/Fishless for 76 days to be sure the parasites are eradicated from the new tank. You could then use your current tank as a QT and treat the fish properly to make sure they are indeed disease free. Then once both processes are complete add the fish to the new tank.

You would then also have to properly QT any new additions as you add them to your disease free tank. This "Should" solve your problem.

 

[Porpoise Hork]

Thanks for the input. I had a feeling it may be a parasite or something like that. It'll take some convincing for the wife to agree to leave both up for that long, but given the possibility of something like Brook or similar critter, I'd rather not take the chance of moving it to the new system.

I had forgotten that a few months back my male clown did develop these small fuzzy like growths on a couple of his fins, and got rather lethargic for a few days. I started to worry but he would still eat and move from coral to coral they host in. I was going to pull him out (provided I could catch him) and put him in a small QT tank, but it all cleared up as suddenly as it came on and I haven't seen any sign of it since.

 

[DarthSimon]

I went through this years ago... Like what was said above, the older established fish will never get sick, but all new tank mates pick up something.... Be patient... And don't add anything for 3-4 months... QT new...

 

[Porpoise Hork]

So she's not to jazzed on the idea of having both up for that long, but is not totally against it. She did raise a good question, in that could I use a smaller tank for the QT setup. I have a 20g tall that I am not using that I could transfer them to and use a few clay pots and some PCV pipe for hiding spots. Then I'd be able to treat them in that, leave the corals and rock to live in the 75g and finally have a viable QT tank instead of a 4.5g AIO I had been using.

Now what to do with the inverts.

I have a red sea star, fire shrimp, huge arrowe crab, and myriad of snails... hmm....

 

[mehaffydr]

So she's not to jazzed on the idea of having both up for that long, but is not totally against it. She did raise a good question, in that could I use a smaller tank for the QT setup. I have a 20g tall that I am not using that I could transfer them to and use a few clay pots and some PCV pipe for hiding spots. Then I'd be able to treat them in that, leave the corals and rock to live in the 75g and finally have a viable QT tank instead of a 4.5g AIO I had been using.

Now what to do with the inverts.

I have a red sea star, fire shrimp, huge arrowe crab, and myriad of snails... hmm....

This would be the best idea so if you do have to medicate you use less medication and don’t contaminate live rock

 

[4FordFamily]

So she's not to jazzed on the idea of having both up for that long, but is not totally against it. She did raise a good question, in that could I use a smaller tank for the QT setup. I have a 20g tall that I am not using that I could transfer them to and use a few clay pots and some PCV pipe for hiding spots. Then I'd be able to treat them in that, leave the corals and rock to live in the 75g and finally have a viable QT tank instead of a 4.5g AIO I had been using.

Now what to do with the inverts.

I have a red sea star, fire shrimp, huge arrowe crab, and myriad of snails... hmm....

Inverts need not be treated and will run fallow with the rock and coral.

That spot looks a lot like an infection but it could be brought on by brook or something as mentioned.

 

[Porpoise Hork]

That's good to know.

Thanks for the info.

 

[4FordFamily]

No problem! Good luck!