Need help diagnosing fish health issue

[Spar]

I've touched on some of this in a prior thread, but with new issues want to rehash it out.

Several months ago almost all my fish died due to a velvet outbreak in my display tank. A purple tang and a bangaii cardinalfish survived. I transferred them to a QT, treated with chloroquine phosphate. I left the DT fallow for 90+ days.

I added the bangaii and purple tang back. Both ate fine, were active, but the purple tang died after 3-4 weeks. Nothing noticeably wrong with the purple tang except it kept getting thinner over time.

I added freshwater black mollies to the tank, and all 3 eventually died. The only noticable issue with them was what looked like a bacterial infection over their body... white blotchy look. And they had white stringy poop. I treated with kanaplex+focus in their food for about 6 or 7 days, but discontinued once they died.

I bought 2 yellow tangs and a sailfin tang, treated them with chloroquine phosphate. Added them to the DT, all were active and ate well. About 2-3 weeks in, one of the yellow tangs died after looking thin. Today the sailfin tang died after suddenly losing appetite the last couple days and looking thin. I never noticed any white stringy poop on them so didn't treat for internal parasites. The yellow tang is constantly swimming straight into my MP60's during the day. No white spots to indicate velvet or ich.

The bangaii has always seemed fine, no issues.... strong fish.

I have 3 Foxface in QT that are about ready to move over to my DT, but I feel like something bigger is an issue in my DT, but without any visual indications of what it may be I am nervous keep adding fish to the tank.

Any idea what could be going wrong? There is no coral in the tank yet. I do have some inverts; hermits, snails, starfish, urchin, pistol shrimp.

 

[RegalAngel]

Just curious, but do you treat all fish in the QT with Chloroquine Phosphate? If so what concentration? Any other meds besides CP?

 

[GoldeneyeRet]

Where was you CP sourced?

 

[Spar]

I purchased my CP from Fishman, which is said to be 95% pure. I use 60mg/gallon.

I treated all my fish with CP, but a couple different methods with the new waves of fish:
1st set of fish added back to the DT: CP for 30 days, twice (was paranoid), a couple weeks in between. I did not dose anything like GC or Prazi with this set of fish.

2nd set of fish + my current fox faces: CP for 14 days, then did a TTM, monitored for a few weeks after. I also did two doses of GC for these fish.

For what its worth, I always added Selcon to food. I feed frozen foods like Rod's Food, and also occasionally brine shrimp. I have a little bit of algae in the tank, so I haven't been great about adding Nori for the tang's, probably should be doing that more often. Not sure that accounts for the weight loss of the fish though.

 

[HotRocks]

Tangs definitely need nori. Especially if you keep a clean algae free tank. In the wild the graze all day long. So they highly benefit from nori. I make sure my clips have nori on them for at least 3/4 of my photoperiod.

I use the fishman CP and it’s as good as pharmaceutical grade CP IMO. The concentration of 60mg/g is high enough.

I’m wondering what may be lingering in your DT. Have you added any corals or anything else wet during your fallow period? Any possible contamination?

 

[Spar]

Tangs definitely need nori. Especially if you keep a clean algae free tank. In the wild the graze all day long. So they highly benefit from nori. I make sure my clips have nori on them for at least 3/4 of my photoperiod.

I use the fishman CP and it’s as good as pharmaceutical grade CP IMO. The concentration of 60mg/g is high enough.

I’m wondering what may be lingering in your DT. Have you added any corals or anything else wet during your fallow period? Any possible contamination?

I will make sure to keep Nori clipped on at all times going forward. Nothing has been added to the DT other than QT'd fish.

The only speculation I have is that it is perhaps a stomach parasite causing weight loss. I could dose GC in their food for a couple weeks just to be proactive. My resistance from this comes from not seeing any white stringy poop. Unless it wouldn't hurt anything to try this?

I will be adding my Foxfaces soon, and as much as I hate for them to be canaries, I will monitor them in the DT to see if they look fat and happy over the next month or so. I will keep Nori in there and feed them plenty of other food.

 

[Spar]

Keeping this going on symptoms as I see them:

The Foxface and yellow tang were doing great through 10/6 (2 days ago). I gave them daily Nori since the above posts (2 weeks now) and they readily ate it all. Fat bellies, seemed happy, for the past 2 weeks.

Then yesterday I noticed the Foxface didn't come out to eat. I finally found him breathing hard under a platform rock. The yellow tang was swimming around spazzy also breathing hard. In the YT's spazzy behavior he was slightly bullying the Foxface, but usually they school together up to that point.

This morning the Foxface seemed fine, leaning against a rock asleep as usual with his camo colors on. Will see how he looks later today, hopefully swimming around again.