Backyard Aquaponics
A place to discuss aquaponics

I've only encountered it in Oscars in the past but I think one of my bream has Hole In The Head (HITH) disease.
I used my hydrometer and the water is basically fresh, I've been watering dirt gardens with the water so I guess the salt % is diluted to basically nothing now.
I had slight but measurable ammonia readings and very high nitrates.
Apparently nitrate stress is a probable cause of the weakening of the immune system in Oscars which is likely to be what allows the infection to take hold.
"Pathology
Hexamitiasis is caused by various species of the protozoan parasite genus Hexamita. These are likely present at low levels in the intestines of many aquarium fish where they do no harm. It is only when the fish is weakened in some way that the parasites can multiply rapidly and spread into the rest of the fish’s body. Once the parasites become established in the other internal organs, the fish soon dies."
from - http://www.fishchannel.com/fish-health/ ... amita.aspx

It is curable but the damage/scarring is permanent, you can only stop it from progressing further.

I did a fairly large water change to bring down the nitrates and will do a few more until I'm happy with the level and will salt back up to at least 3PPT to help the bream out a bit and hopefully reduce any stress on them.
This fish had lost a bit of condition compared to the others but still seemed reasonably vigorous at this stage.
When I first noticed the fish it seemed to have large nodules on its head but there are none now (if there ever were) and there are only little craters where they had seemed to be - in a crescent above both eyes and in another line further up on its head with some more on the side of the head.
Only one fish of the three affected at this stage.
I may cull it yet, surely it would still be safe to eat?
(Annoyingly the camera decided to focus on my fingers and I didn't notice because the bright sunlight made it too hard to see the pic. Don't really want to net them out again unless I have to).

I forgot to ask if anyone has encountered HITH disease in AP?
I found an article that mentioned the infection in nile tilapia but only for purchase, so I didn't get to read it.
Would like to read it in case it mentions anything about them being unfit for consumption. Ideally I'd try to get it to heal before harvesting but I'm pretty tempted to just remove it from the system.

Not eating this one, I went outside to check nitrate levels after the water change and found it floating. (Nitrates are still very high, at least 80ppm, possibly higher...)
Didn't catch it early enough it seems. All the more reason for FT windows perhaps?
The other two fish are showing no signs of infection so fingers crossed.
Pics show the surprising extent of the erosion on the head of the unfortunate thing. For some reason it didn't seem this bad when I saw it before.
There was also an infected area between the pectoral fins of the fish so I expect that the infection had spread to the organs. I suppose I should autopsy that in case anyone is interested. Apologies for the pics, my phone isn't the best camera.

The fish was 30cm overall length and 480grams, no idea of it's size and weight when I put it in the system but there hasn't been much growth. Somewhere between 0cm to 3cm in almost 6 months I'm guessing and I think it looks like it has lost some condition due to this illness. Apart from the obvious erosion symptoms of HITH, it seems like it should have been healthy if slightly starved.
Brick in the last pic for comparison.

edit
Other factors that are said to increase the chances of HITH in susceptible species include -
- Increase in, or fluctuating temp in the FT
- decrease in dissolved 02 due to temp increase (or other reasons?)
and other things that would generally stress the fish I suppose but I specifically read about those two.

It would be interesting to know what actually killed this fish. Edwardsiella ictaluri the cause of Enteric Septicemia of Catfish (ESC) can cause it's own version of hole in the head disease. It can also infect other types of fish.

http://en.wikipedia.org/wiki/Edwardsiella_ictaluri
http://www.thefishsite.com/diseaseinfo/36/enteric-septicaemia-of-catfish

This last one is a Word document for Australia (gives some of the susceptible hosts in a table form) -
http://www.agriculture.gov.au/.../animal.../enteric-septicaemia-of-catfish.doc

Might be useful, might not

I've had hole in the head disease many times this festive season

Oh dear Bodgy, you managed to sneak your toes into the photo.



Ask Charlie what a long off-topic discussion that caused on his thread.

Charlie in your case I fear it is permanent.

I here posting animated yabbies is diagnostic

Haha

Unfortunately for me not being able to spell is an early sign