Backyard Aquaponics
A place to discuss aquaponics

Could also be dropsy: (http://en.wikipedia.org/wiki/Fish_Dropsy)

Internal bacterial infection, causes swelling. are those scales sticking out at all? Looks bad whatever it is.

It also looks a bit "Milky cloudiness on skin" - http://animal-world.com/encyclo/fresh/i ... seases.htm

That is my guess, fluid build up in the body cavity

Here are some details:
Dropsy - Fluid Build Up In Fish

When liquid accumulates within a fish's internal cavities or tissue it is often referred to as dropsy.
Affected fish will be noticeably swollen in the abdomen area.
As the ailment progresses the scales will begin to stick out like the surface of an open pine cone.
Fish become lethargic and lose enthusiasm for eating.

Causes Of Dropsy

The causes are varied and more than one factor usually contributes to the dropsy.
Poor water quality or incorrect chemistry are dominant pre-cursors.
An insufficient diet lacking the correct foods is also a dominant factor.

Bacterial agents are regularly associated with the swelling but these can usually be considered secondary to environmental and diet factors.

Dropsy Treatment

Addressing the water and feeding issues is the first step that should be made when treating dropsy.
Antibiotics and other medications are also sold for this purpose.

Unfortunately treatment is usually ineffective.
This is due to internal damage that can occur from the pressure associated with the swelling.
Some fish may appear to have made a full recovery but die days or weeks later for no visible reason.

Also see:
http://www.fishyfarmacy.com/fish_diseas ... avity.html
http://en.wikipedia.org/wiki/Fish_Dropsy

HTH

Thanks for all the info. Dropsy sounds consistent with the symptom of bloating. Clearly there is something horribly wrong with the water in my system, and it is not ammonia, nitrite, nitrate or temperature. (Even pH of 8 isn't too high for goldfish.)

Specifically answering Vegieman's questions:



They're all goldfish (or "Comets" as they are called in the petshop). When I bought them at the shop, they appeared to be all the same variety in a coldwater tank together. I doubt whether they would have been mixing with tropical fish. The fish are mostly the same colour (orange) except for one that's white, one that's brown and one that had a black blotch. The blotched one died a few days ago. The white one is still going strong and as far as I know the brown one is, too (last seen a couple of days ago).



I don't know if they have all been feeding as normal - I don't stick around to watch all the time. I have seen at least one fish feeding well in the past few days. I haven't fed them this morning (on the fear that I have been overfeeding).



The water refill line was shut off last week to avoid further Zinc contamination (just reinstated this morning, using mains water - now refilling slowly via float-valve, whenever pump is running).

Ammonia went up and came down, has been zero for last five days. Nitrite never registered in my tests (using proper API drops for testing, not the swizzle strips). Nitrate went up to 5ppm and has now come back down to zero (perhaps taken up by plants?).

Additions to the system:
Seasol has been added 2 capfuls at a time about once a week.
Chelated iron has been added twice - one teaspoon per growbed on 31 Jan, and again on 11-Feb.
2.7 kg Pool Salt added on 7 Feb (this should take concentration up to about 1ppt)
"pH down" added 7 Feb (150g), 8 Feb (150g) and 20 Feb (200g).

It would appear that the cause of your problem may well be in the pH/Temp status.
Your charts show a marked period of unstability in the water parrameters between 6th Feb and 11th Feb.
The combation of the pH and temp are certainly more than enough to trigger a bout of Dropsy.

Unfortunately Dropsy can become quite prevelant once fish start to circum to its effects.


There are meds out there to treat it, but as to the effects on BYAP I couldn't say.

One such treatment is
Aqua Master Aquari-Cycline - http://www.aquaticlifeaquariums.com.au/index1.html

You could even try Epsom Salts I have heard that it can help in conjunction with products such as Aqua Master Aquari-Cycline.

Unfortunately you may well lose more fish before the problem goes away
But on the bright side, they are only Goldies at this stage, get the water right before you go SPs or such, otherwise the problem may well re-occur.

HTH

OOOps, link is not direct to product.
If you visit the site please follow these links [in the navigation to the left of screen]:
* Aquarium Products
* Medications
* Bacterial Treatments

Another one down... Exactly the same symptoms.



I've updated the charts to show when the current batch of goldfish was added to the system and when the deaths begin. (Also fixed up the image quality.) These fish were added at the end of the heatwave, so those horrible extreme temperatures have not affected them.

The dropsy could have been caused by the fairly rapid spike in pH starting around 13th Feb...? I've lowered it now and probably did so way to fast (it's down to 7.2 already) - this change may be enough to kill the remaining fish

So the main lesson learnt is to "nip it in the bud" whenever pH starts to creep one way or another, rather than allow it to get too high/low and then force a rapid correction.

I am also forming a theory that the pH is high due to the high levels of Zinc (water reacts with Zn to form ZnOH, which is a base).

There in lays your problem, but a valuable lesson learnt.
Unfortunately I think you may well lose more fish before you see the end of the problem as was quoted earlier, Fish can show no signs of Dropsy and appear normal, only to curcum to its outcome the very next day [In some cases HOURS]

I would personally remove the batch from the system, thoroughly clean and disinfect all the set up [I know, a real a in the proverbial, but it is that, or run the risk of the Dropsy spreading to future stocks [particularly for human consumption].
You could house them in another quarantine set up if you really want to try and save them, but honestly, the effort would far out way the benefits.

I wish you luck

p.s. What script are you creating your data charts with, it looks to be a fairly basic yet informative system?

Charts are standard X-Y scatter plot (MS Excel), and I'm manually drawing the red lines and text boxes ("goldfish added" etc) on the charts.



Thanks. When you say "thoroughly clean and disinfect all the set up", what do you mean?

Let me guess... Water change, right? This is devastating; all the alleged water efficiency in aquaponics seems to be wasted ten times over by water changes when things go wrong!!!

Incidentally, the fish deaths all appear to be occurring in the sump, and the fish in the other tanks still seem very happy. Is it normal for dropsy to NOT be transmitted by the water? I wouldn't have thought this to be the case, as the theory is that it's the pH / Temp change (which is happening system-wide).

One other thing is that my wife put some duckweed (Azolla) in the sump only... I don't suppose this would have anything to do with the problem? The Azolla came out of another pond in our backyard that I guess might have some nasty things in it (filled with mains water, relatively high evaporation so high concentration of dissolved salts, water hardness etc, dog drinks out of it...)

Here's a plan...

Remove the fish, then chlorinate the water fairly heavily. Wait a week or two for the chlorine to gas off, add a chlorine neutraliser, then re-stock with new fish.

What do you think?

Some people sterilise their growbeds with bleach because it breaks down to ammonia and it can then be converted to nitrates. I think a partial water change would still be needed after the bleaching. I would avoid chlorine because it is toxic to fish and most dechlorinators are also bad for fish/people hence the "not for fish for human consumption" labels on the bottles.
Im not sure which bleach you want but im sure it should be as pure as possible and i don't know how much you need. Can someone more knowledgeable than myself help out here?

Must say that I still can't help thinking that there is an underlying issue here.
The level of Zinc could well be it.
I'm no chemist but I don't think bleach/chlorine will solve the issue.
I know it's hard, but I would be tempted to have a fresh start.
- Drain the tanks onto the dirt garden (maybe give some to your neighbours if you are feeling guilty)
- Remove GB media and give the galv GB's a coat of Gripset 51.
- Wait a couple of weeks and rinse.
- Refill system with mains water.
- Ask some friendly AP'ers to give you some "gunk" to help cycle the beds.
If you do this soon, you will have a clean, no stress system ready for trout season.
Wish you all the best whatever you decide to do.
Cheers

Hmmm... I am inclined to agree. The one thing we never tried with Dad's system was a fresh start - we always tried to fix the system he had. This meant the water never got changed, and the gravel never got emptied. As I've mentioned, that system failed dismally.

All in all, I think it's a good idea and as you say it gives me a chance to seal the GB's.

Looking forward to trout season

Bloody Fish can be a real pain sometimes but I really think that you are making the correct decision.

TIP 1:
Try using a 50/50 mix of White Vinegar and Hot Water applied via a scrubbing brush.

TIP 2:
Follow this [after allowing all system components time to thoroughly dry in the sun] with a 50/50 mix of Sea Salt and Epsom salts. That should eliminate all nasties that may be lurky in the system.

TIP 3:
Before you start this process clean and fill atleast one or two good size drums with water and add an airstone to help age the water. If you have an aquarium [or friends that do] try to get a reasonable amount of tank aged water, you will find that this will help to trigger the system following the clean up.

HTH

I agree get that zinc covered up and out of the system and then see if you still have a problem. It has to go either way because it will cause problems in the future even if its not the problem now. Fix the zinc problem now once and for all and then things will start to come together, I really feel you have taken one for the team on this issue of zinc and there is only one solution.