Clinical Signs |
Possible Causes |
Sudden death of many fish over a short period of time with few preceding
symptoms. Surviving fish hang around the water surface / stay on the bottom and may
lose equilibrium. They are lethargic and don't eat. |
1) Acute
poisoning. Water should be tested for core parameters and fish examined for
signs of severe parasite or bacterial infection. If possible, post mortem
recently dead fish. If these are negative carry out a 75% or more water change
on the presumption of some (as yet, unknown) toxin. Send water sample away for
toxicology testing.
2) Low dissolved
oxygen levels. Measure levels in pond/ filter early in morning when DO levels at at
their lowest
3) Peracute bacterial disease. Diagnosis would require post
mortem and aseptic bacterial sampling of organs |
Fish rub against solid objects and
"flash" when they turn to rub their sides giving a flash of colour as
their undercarriage is exposed. They may also leap out the water. |
This indicates
some form of irritation of either the skin or gills.
1) This could be
caused by raised levels of ammonia, nitrite or high/low pH. Widely fluctuating
diurnal shifts in pH can also cause irritation. Check
all water parameters.
2) Irritation can
also be caused by ectoparasites such as flukes, Trichodina,
white-spot etc on the skin or gills. Do a skin
scrape of 2-3 fish. Examine the gills. |
Fish swim normally but appear to be
breathing heavily. (This can be judged by operculum movements).
Fish appear to be gasping, they may
crowd water inlets |
1) Hypoxia.
Dissolved oxygen levels may be low, test levels early in morning.
2) Poor water
quality causing gill hyperplasia, excess mucus production or nitrite toxicity. Check ammonia, nitrite levels and pH. Check
that pond and filters are clean
3) It could
indicate the early stages of gill disease. If the
condition persists it is important to examine 2-3 fish for gill parasites or gill
disease.
4) Gill parasites.
Take gill and skin scrapes
5) Anaemia. Gills
look pale |
Individual fish stay apart from others. Breathing is
normal. They may refuse food. They may have "cloudy" or grey areas
on the skin. There are no other physical signs. |
Lethargy and
inappetence are common symptoms of many diseases, so further investigation is
essential
1) Fish may be
suffering from a parasite problem. Take a skin and gill scrape. Examine the
gills.
2) There could be
internal disease problems
3) Early stage of
systemic bacterial infection. Isolate and observe
4) Test core water parameters |
Several fish are lethargic. Fish are not eating or eating very
little. Fish are skittish and shy. Some fish may have split or ragged fins |
Lethargy and
inappetence are common symptoms of many diseases, so further investigation is
essential
1) Poor watery
quality. Check ammonia, nitrite, pH.
2) High levels of organic pollution.
3) Ectoparasite infestation. Check 2-3 fish for parasites or gill problems.
4) Early stage of bacterial disease. Examine fish for lesions, inflammation
and ulceration. |
Overproduction of gill and/or skin mucus.
Grey slime/ trailing mucus. May be accompanied by rubbing/flashing, heavy
'breathing' and/or lethargy. |
1) Ectoparasites. Take skin and gill scrape
2) Poor water
quality. Test core parameters |
Skin lesions or ulcers
Reddening or inflammation on the body or fins. Raised scales.
Localised swelling. Open wounds or lesions that do not heal within a day or two |
1) Physical
damage. This will normally present as a 'clean' lesion with little
inflammation. Usually heals within days. Always a risk of secondary infection.
2) Local tissue
irritation caused by ectoparasite infection. Take
skin and gill scrape
3) Bacterial disease
4) Water quality
problem. Test core parameters
5) High levels of
organic pollution. Check pond and filters for
decomposing solids |
Focal red or white lesions on the body |
Larger ectoparasites such as lice, leeches
or anchor worms. These parasites are normally visible with a close examination |
Fin rot
Frayed, split or ragged fins. Possibly with whitish edge and some
reddening of the fins |
1) Bacterial infection
2) Ectoparasite
infection. Take skin and gill scrape
3) Poor
environmental conditions. Test core parameters
and check that the pond and filters are
clean
4) Physical damage
5) Over crowding
6) Saprolegnia (fungus) infection
7) Columnaris
infection (mouth fungus/cotton wool disease) |
Fish has swollen abdomen (dropsy). Possibly raised scales and
some reddening on the body or fins. Possibly pop-eye (exophthalmos) |
1) Viral
infection.
2) Systemic bacterial infection. leading to 'dropsy' (build up
of fluid in the abdomen. Can be differentiated from tumour by shape, symmetry and
feel (feels soft and fluidy)
3) Neoplasm
(tumour). Can usually be determined by size, shape (usually asymmetric) and
palpation (feeling - usually hard)
4) Heart or kidney
disease. Can only be diagnosed by post mortem
5) Internal parasites (endoparasites)
6) Genetic
disorder
7)
Intestinal blockage. Only established at post mortem |
Respiratory problems. Gill examination shows areas of necrosis
(dead tissue), mottled appearance, heavy mucus |
1) Bacterial gill disease
2) Viral infection
3) Branchiomyces (gill rot)
4) Gill parasites. Take
biopsy/ scrape for microscopic examination |
Tiny white spots, as though fish has been
sprinkled with salt. Usually with thickened mucus |
Ichthyophthirius (white spot). Definitive diagnosis by skin scrape |
White or or discoloured 'cotton-wool'
patches on the skin or fins. Often accompanied by inflammation and skin erosion |
1) Saprolegnia (fungus) infection
2) Columnaris
infection (mouth fungus/cotton wool disease). Take sample for microscopic
examination which would show typical long 'gliding' bacteria (Flexibacter sp). |
Swellings on the skin
|
1) Parasitic
cysts. Take 'deep' skin scrape
2) Physical
damage. Examine fish and observe
3) Bacterial
infection. Usually accompanied by inflammation and raised scales. Examine fish for inflammation and/ or raised scales.
4) Internal
tumours
|
Growths on skin / fins |
Tumours or viral
infections such as;
1) 'carp
pox', which resembles melted wax poured over the fins or skin
2) papillomas,
'warty' types of growths, can be quite large, smooth or cauliflower-shaped, white,
red or pink
3)
lymphocystis, various sized, white to pink masses on the skin and/or gills.
Diagnosis is by microscopic examination of 'wet mount' taken from the lesion.
* There are no
treatments for these growths. They are usually benign and often self-resolving.
There is always the risk of secondary bacterial infection |
Corneal Opacity (cloudy eye) |
1) Physical damage
2) Nutritional
deficiencies
3) Poor water quality
4) Bacterial infection |
Skeletal deformities / kinked spine |
1) Electrical
shock. Faulty electrics or lightening strike
2) Use of organophosphates
3) Nutritional
imbalance
4) Genetic
abnormalities
5) Muscular damage
/ physical damage
6) Toxins
Unless there is an
obvious known problem, it is difficult to establish the cause. A radiograph (sort of
x-ray) would assist for skeletal problems |
Loss of equilibrium with fish unable to stay upright. Fish may be
able to maintain position when swimming, but turn over when they stop swimming. |
1) Swim-bladder disorder / disease caused by viral or
bacterial infection, constipation (mainly fancy goldfish) or other organ disease.
2) Internal organ
disease, i.e. kidney / intestinal disease or blockage. Usually only
established at post mortem |
Lethargy, weight loss, chronic mortality. May be worms protruding
from anus |
1) Internal
parasites (endoparasites). Requires blood sample, wet mounts from dissected
tissues and wet mounts of faecal sample |