Old Age Or Something Else?

[Akasha72]

Hi, I'm looking for another pair of eyes over what's going on in my tank as I can't decide if it's just elderly fish or 'something else'
 
So, I've lost nearly all of my black neons over the last 6 months - I'm now down to four. I've also lost a lot of my harlequins - lost another last night and I've also got an old peppered cory female acting strange.
 
The symptoms in the neons and harlequins are very similar. They start to swim erratically with tails down, noses up and don't seem to have the strength to fight the filter current. This goes on for up to 2 weeks before I find them dead. I had 10 neons just over 6 months ago. Another thing I've seen in the neons is black marks on various parts of their bodies - one had a black mark on it's stomach - that one died a while ago. I now have another with a black spot under it's chin and it's showing signs of swimming funny now. I doubt it will be with me for much longer.
The harlequins have no marks on them they just start this swimming funny business and die. The new harlequins are all well, this is only affecting my older fish. I'd say my old original harlequins are around 4 years old - the new additions are from this year so they are less than a year old.
 
My cory female is also one of my older fish - she's probably about 4 to 5 years old at a guess. She's often found in a corner looking like she's dead, her body is bent over (like they go when they are dead - sure you all know what I'm trying to describe) She's also allowing her tail to raise up before pulling it back down. 
 
My thinking is this is an old age thing as all my younger fish are perfectly fine but there's a small part of me just doubting that a little bit. It is a lot of fish to suddenly die one after another and I just wanted to check that this isn't anything else. There has been some new additions to my tank but all those fish are perfectly well so I can't start thinking they have brought something in.
 
Thoughts?
 
This tank has been running for nearly 2 years, both filters are well established and so this isn't a water quality issue as all my important stats are fine.

 

[Akasha72]

video http/vid1127.photobucket.com/albums/l634/akasha3472/002_zps4mpoivck.mp4

 

[RobRocksFishTank]

Three things come to mind. You are not going to like hearing them but they need to be said. Please do not call me a bully again.
 
You did something different recently, black water. That would be my first guess.
 
You moved the tank recently. Maybe something happened during the move.
 
I know in the past that you've had water conditions that were questionable. Maybe that is finally showing its long term effects, which you were warned about.

 

[Akasha72]

not the blackwater - that's been there just 3 days - re-read my original post - this has been going on for around 6 months - same reply for moving the tank which was only 6 weeks ago. As for questionable water - nothing wrong with my water for the fish I have. That much have been proven - apart from my SAE's all my fish are soft, acidic water loving fish and are perfectly fine for my soft acidic water

 

[RobRocksFishTank]

Okay, scratch the first two.
 
As to the water conditions, that is a matter of opinion. Your fish may have seemed fine but what you are seeing sounds like the symptoms of long term stress.
 
I doubt if it is age, the deaths are too close together.

 

[Byron]

I am the last person to advise on diseases, as I have basically no experience except with a few oddities.  But I see in your video some things I have myself experienced, so I will offer a few comments.
 
First thing I'd like to mention is that Rob has raised very important factors, some of which have been eliminated here but in other situations could well apply, so they are worth having mentioned.  But the last, namely physiological impacts from stress or injury in the distant past, is certainly relevant.  I have often written that fish may live through this or that but down the road they show the effects because unseen internal damage has occurred.  Without dissection we usually cannot confirm this, but be assured it does occur.  This is why I am so adamant on not adding unnecessary chemicals and substances to the water.  This is not applicable to you Akasha, so please don't misread me, I am merely pointing out my reasoning which some do not seem to grasp.
 
The black neon in the video seems to have a white patch on its chin...not sure at all what this is.  As for the swimming difficulty, I have seen this in characins, sometimes cyprinids.  I acquired a group of Hemigrammus pulcher a couple of years back, and almost every single one went like this and died, over a period of several weeks; it began a few months after acquisition.  In this instance, the fact that I have had a number of disease issues with other fish acquired from this one store, and with no other fish acquired from individual importers, led me to conclude that there was something originating either at the fish farm, supplier, or the store.  It is one of the chain stores, so this is quite possible.  I have never to my knowledge had similar issues with fish acquired from direct importers from the wild or with more specific retailers that have set fish farms.  The coincidence is too great.  All three species in your tank affected are commercially farmed fish, not wild caught.  This undoubtedly plays a part.
 
As to what it actually is that causes this buoyancy problem, I don't know.  But characins have to work continually to maintain their even keel.  If you watch them closely, you will see they regularly sort of jerk to do this.  This process may be readily affected by stress, etc.  Many other fish, such as catfish, cichlids, etc, do not have this need.  Any and all stress occurring to a fish can have serious unseen consequences, as Rob mentioned, and I alluded to above; this can be something that happened before you ever saw the fish in the store, or during netting, etc.
 
Without implying that it is the cause here, I would like to respond to your comment about new fish not bringing in something because they are fine.  Fish can readily carry disease but never themselves succumb, but it can quickly spread to the existing fish.  The fact that newly-acquired fish remain healthy, externally, does not mean they may not have passed on some internal issue to others in the tank.  And even those of us who quarantine for weeks cannot always escape the consequences.
 
I don't see any of the black patches in the video...did I miss them?  I am curious if this is what I have spotted in a few fish recently.  I had one female Black Phantom where the lower edge of her body from behind the vent to the caudal fin became black, visible on both sides so it was through the fish, for about 2 mm up.  She continued swimming and eating with the others, and showed no difference in behaviours.  After a few weeks, a hole developed mid-way that went right through the fish; I could easily see through it when she swam slowly.  She lived on for a few months.  I've no idea what this was.  One of the Rosy Tetra in this tank also has a black spot on the caudal peduncle, and has for some time.  No other fish (and there are over a hundred in this tank) have shown this.  ??
 
Byron.

 

[elmo666]

Hi Akasha. Don't believe old age is the cause here, and all that Byron says is relevant. I've been fortunate in so much as I haven't had many fish losses as my experience has grown over 30years of keeping fish on and off. That said perhaps one area most of us fall down in, myself included, is properly quarantining new fish. This could be down to not having the luxury of having the facilities to or not seeing it being needed.
Now, just before Christmas last year I decided to add a shoal of 40 cardinals to my discus tank after I removed a number of large emporera tetra. All appeared healthy at the time of purchase, settling in nicely. However, over the next few months I lost 10 or more without any visible signs of disease. They hadn't lost any weight, nor did the act in anyway odd. I believe this is relevant to your post as I am sure they must have been carrying some form of bacteria or virus that only is an issue if the fishes own immune system is lowered in some way such as the stress of moving etc. This is why I think not all my fish succumbed to it, being individuals as they are.
Damian