please comment unexpected undefined health isssue

I need some opinnions, please.
About 1 month ago I consolidated 14 wild adult discus (8 heckels, 6 between browns and greens) into a 150 gal barebottom tank. I did a metro treatment and elevated the temp to 92, and is back at 88, then it will be 86-87.
All along everybody looked great, until today, one large heckel has me very puzzled.
He gets very dark and begins to act as a tail-stander, almost vertical. Sometimes he moves his dorsal/anal fins as in a shaking motion, while tailstanding. He lasts like that for 5-10 minutes, and then resumes normal color and position, although appears lethargic. A while later, same tail-standing/dark deal again. In addition, one of his pectoral fins appears clamped against the body, and stays this way even when the fish resumes "normal" swimming and coloration.
When he is tailstanding, he looks very bad, like dead, but there is no accelerated breathing.
Not knowing what this is, I opted for no feeding tonight, and performed a regular water change (I have been changing 60gal daily in the nominal 150gal, so about 40+ percent). I also added Epson salt at 1 tablespoon/10gal.
Could anybody comment or suggest on possible reasons or what to do ?
pH=7.6, Prime-treated and aged tapwater, 350-400 microsiemens, 2 feedings/day (morning flakes or various bits, afternoon any of: beefheart, mysids, bloodworms, red wigglers).
Thanks & chhers, Francisco

up.

Comments, please. 24 hours and no changes. Symptoms come, look really bad, then get better, then come again.
Cheers, Francisco.

Thanks for the overwhelming level of response/support....

Unfortunately, the fish looks much worse today, but symptoms appear the same, only that the "bad periods" (dark, vertical with tail down, shimming) are longer. I don't think I'll add Epson after today's water change, as he doesn't seem bloated. A bummer and a mystery. I hope it gets better. It is the only one out of 14 fish in a 150gal.
Francisco.

Hi Francisco, just want to share exp.

I had the same experience, lost 4 of my discus.. my fish acting like that for 3-4 days but i thought he bloated a bit then i did eps. 2-3 tsp/10gal. and the situation seem better, afterthat the black symptom, head and tail stand happened again i used some antibiotics but it didn't help and he died in the next 2 days.

Unfortunately, this symp. happened to other 3 in the same tank and guessing......died all. :'(

only thing that i can comment is if you didn't isolate him, pls. do it asap. but for the treatment i hope some expert could help...

best of luck,
Preeda

My guess would be an intestinal blockage.

Mat :)

I don't know Fransisco, sounds like a swim bladder infection, but I do not know that they would come and go like that. Wish I could provide more info for you. ??? Frank

. . . . and I don't have the answer either. DPH has an article by Robin Futtrell on how she treats head and tail standers by lowering the water level. I'd sure try that and an antibioitic like Kanmycin in case it is a bacterial infection.
Sorry Francisco :-\
Carol :heart1:

Thank you Praeda_Lim, Mat, Frank, Carol.

The fish is still in the show tank, but I will take it out this afternoon. I will try Kanmacyn as well. What a bummer. It is a nice, fairly large heckel, although his shape is not the best (he is a bit off-round, somewhat of a flat top shape), but this makes me feel no better.
Interestingly, he has been eating, although not much, and does not seem bloated. The weird thing is that of one pectoral fin being clamped against the body at all times. I don't know if the fin deal is part of the problem, or a separate, coincidential issue. When he is not doing the "bad thing", his color and everything seem okay, except for the fin.
I guess I will see more of this. Thanks again, Francisco.

Hi Francisco,
That behavior sounds alot the behavior some of my fish do, when attempting to interest a tank mate to spawn, in a community tank. I have at least 2 pairs that were formed like that. I thought the fish was ill the first time I saw it. looked almost like a dolphin doing a tail dance, but very slowly.

next time it does it, note the fish that are around it. You may have a potential pair there. I'd leave it in if theres no other sign of illness.

I could be way off here.

hth,
al

Thanks Al. You may not be that far off after all. Tonight the fish appears better, but does have moments of darkness, but not as dark, and has not been tail-standing. Of course I just got home and the night is young.
He has not seemed bloated from the beginning, he does eat but not a lot, but ate California worms tonight eagerly. The pectoral fin deal also seems better, and I now am fairly certain that that is something else (don't know what) unrelated to the tail-standing. He is using the fin some now (as oppossed to nothing, nada, zilch before).
He does seem to do its (his ?) thing towards one fish in particular (I did not even realized this before): one large, plain peruvian green that has the worst attitude I have seen in a discus. It (and another green in the tank) are selfish, mean, aggresive, territorial, and .....plain. The green one pays attention buy expressing aggression. If they are doing a pairing thing, I am excited, but they are far from the best potential pair among the fish in the tank.
But I am still not sure and don't rule out a health issue yet. He does seem better and I am opting for waiting until tomorrow for any action such as separating it or thinking applying any procedures/meds.
Thanks again everybody. I'll keep you posted.
Cheers, Francisco.

update:

Fish continues to improve, but continues to do his thing at times. His pectoral fin is also improving as he uses it more and more.
I still don't feel certain of any of the possible causes: a bacterial problem, a bladder problem, his weird personality, sexual display/offering.
Thanks for all the comments. Cheers, Francisco.