Discus Dilemma

[elmo666]

Hi guys. Normal 70ltr water change on my discus tank Sunday (80/20% ro to filtered tap water). Monthly parameters checked, all good. Set up as per signature below. What I came in to was my normal lively and inquisitive fish ( they tend to "follow" me around the room) grouped in a huddle under the large bogwood with increased resps. Very odd.....and worrying......unless ofcourse they're Brazil fans?? .
Anyway, angled one of my returns to give a little more surface ripple, went to bed. This morning all fine demanding a feed at the front, great colours, so what's going on?? I've had this several times and never found a cause. I regularly test ph, kh, nitrate. Have TMC ammonia and ph alarms in tank as well. On every occasion water checks out fine, even when I double check for ammonia and nitrite. The only test kit I don't have is for dissolved oxygen, but really can't see this being an issue with so much water movement and good surface ripple. Am I missing something obvious?? I don't suspect my co2 as this is on a daily timer , 1 hr before lights on, 1 hr before lights off, 6hrs in total. If anything my co2 is a bit on the low side at 1 bubble per second, but most of it does go into an uplift to maximize contact time. Any suggestions as to cause will be gratefully received as I got up 3 times in the night to check on them. Thanks.

 

[bluesword23516]

Sometimes fish need time to adjust to new water. I have noticed it happening to my fish when I do water changes and it is normal.  

 

[elmo666]

The worry is that the change was done Sunday morning, I do one Sunday and Wednesday, the stress I saw wasn't until last night, 48hrs later. Would have thought an adverse reaction to the change would have happened sooner. What do you think bluesword? Btw, the water is circulated and heated overnight and the ph is matched to the tank, using the tap water to do so. The tap water is passed through a 3 stage carbon filter. I also use pro discus mineral to correct the r/o.
The problem I saw last night, although I've seen it a few times, its not a regular occurrence. Tbh it baffles me, unless they're just being bloody moody, all other tank occupants are unaffected.

 

[bluesword23516]

Oh, didn't notice the dates of the water changes. Thats kind of weird... what time did you see them when they were like that?  Also what was the water temp? Maybe if it had suddenly raised they were lacking oxygen in the water and thats why they were staying still and breathing hard.    That is all I can really think of. 

 

[elmo666]

The time I spotted them was around 7pm Tuesday, I think I finished the water change 11 a.m. Sunday. Both heaters in my 25 ltr buckets give a temperature of 82, the same as my tank. Got to agree with you, its weird. The other odd thing is that if it is a lack of oxygen I would have expected to see them hanging near the surface where levels are higher. Very odd.......