Chilodonella?

[aquila]

Tank size: 180l
pH: 7
Ammonia: 0
Nitrite: 0
Nitrate: 5-20
Tank temp: 16c

Fish symptoms (include full description including lesion, color, location, fish behavior): The first fish to die was lethargic and bottom-sitting. Checked water parameters, all fine as usual, and as fish was still eating left well alone. Two weeks later an ulcer appeared on the fish's belly seemingly overnight, the fish was immediately isolated and treated with salt and melafix but died 48 hours later.

The second fish became ill an entire month later. Again lethargic but still eating well. Fish suddenly 'pineconed' for around 24 hours but appeared greatly improved after a salt dip/bath. Fish then died with no other symptoms 24 hours later. No lesions or marks on body (black fish so any white marks would have been easily seen), no 'flashing' or rubbing, no respiratory distress.

Remaining fish is still mostly actively swimming and appears well but I occasionally catch her bottom-sitting and I might be being paranoid but there may be small white marks around the head - not ich or fungus but pinhead sized white growths, too small to take a photo of and hardly visible out of the water.

Volume and frequency of water changes: 50% weekly

Chemical additives or media in your tank: None, running 1 x Fluval 205 filter and 1 x Fluval 305 filter, standard media, dechlorinator used for water changes

Tank inhabitants: One female fantail goldfish, approx 8" long excluding tail (12" with tail), five years old. Two similar fish (slightly larger and older) now deceased.

Recent additions to your tank (living or decoration): None

I'm really puzzled with this one, it's a mature tank with mature fish and a stable maintenance routine. With the remaining fish I have been treating as for chilodonella as it's pretty much the only thing matching the symptoms (i.e mysterious!) but none of the fish have displayed respiratory distress or other behaviours associated with parasites. I've dosed the tank with Interpet Anti Slime and Velvet (copper-based, says it treats chilo) and have been bathing the fish every other day in a 3% salt solution with more of the copper treatment as well.

Any other suggestions? I don't want to lose the last one, it's been heartbreaking to lose such big old fish.

 

[WILDER]

Any redness to the pin head growths.
Do the pin head growths have any strands coming out of them.
Do the pin head growths move.
Do the pin head growth form a cluster of eggs.

It dosn't sound like a parasite to me if there no signs of darting, erratic swimming, flicking and rubbing, exess mucas, or slime, laboured breathing.

Ulcers will be pink or red with a circling of dead white tissue around the edges.
Causes of ulcers are bacterial, parasites, bad water quality, viral.

Chilodonella



Symptoms:

The skin and gills become discolored, taking on an opaque, bluish-white to gray coloration. The area between the head and dorsal fin is generally the most severely affected. In advanced cases skin begins to swell, eventually shredding and falling off in strips. Gills are also affected and may be completely destroyed. Clamped fins, listlessness, hanging at the surface and gasping may also be seen. The fish may rub or scrape against objects in the aquarium in an attempt to relieve irritation.



Cause:

The ciliate Chilodonella cyprini. These heart-shaped parasites, at a size of 40 to 60 microns, are not visible to the naked eye. The parasites are able to swim freely, spreading easily from fish to fish. Reproduction occurs by asexual division.



Treatment:

Highly infectious and able to kill in great numbers, Chilodonella may very well be the most dangerous skin parasite there is. Overcrowding increases the risk of infection. Acriflavin Plus, Malachite Green, Paraform, Quick Cure or Formalin are the drugs of choice for Chilodonella. All fish as well as the aquarium they inhabit should be treated.