by the crustacean Ergasilus
found attached to gills, gill covers and inside the mouth. Heavy
infestations with Ergasilus can cause severe gill damage,
emaciation, anemia and even death.
TREATMENT Treat the whole tank with organophosphorus
insecticides such as metriphonate (0.25-0.4 mg / liter, continuous
bath for 7-10 days, may need repeated). If fishes sensitive to this
medication are present (e.g. piranhas), treat them separately with
potassium permanganate (30 minute bath).
PREVENTION Maintain a much higher standard of aqua
system hygiene, paying particular attention to filter cleanliness
and avoiding overfeeding. Always stir up filter-bed before siphoning
off old aquarium water when carrying out a partial water changes.
Never use non-irradiated seafoods, Daphnia, Tubifex, bloodworm,
with certain fungi (such as Branchiomyces),
bacteria, protozoans and monogenetic flukes (like Dactylogyrus)
and / or poor water quality.
SYMPTOMS Rapid gill movements, swollen gills and
discolored gill filaments with excess mucus. Fish do not eat, lie
motionless in the tank or gasp at the water surface.
TREATMENT Improving the general water conditions often
eases the problem. Making a prompt 30-50% water change with
conditioned water is a good initial treatment. You can also add one
of the aquarium antibacterial remedies.
PREVENTION Keep good water conditions and perform
regular water changes.
Caused by the larval stages of freshwater
mussels such as Unio
SYMPTOMS Grey edges on the fins and / or gills are the
most obvious symptoms. Can be quite pronounced in heavily infected
TREATMENT No special treatment is available but
luckily, this situation is not dangerous.
PREVENTION Remove adult mussels from the tank while
they are shedding their glochidia (larvae) during the summer
Caused by the ciliate protozoan Tetrahymena
SYMPTOMS The visible
symptoms are very similar to those of white spot disease.
TREATMENT A proprietary brand of white spot treatment
will be effective. However, well-established infections may require
PREVENTION Keep guppies in warm, moderately hard,
- body flukes (see Flukes)
Caused by various bacteria, including Aeromonas,
Pseudomonas and Vibrio.
SYMPTOMS Lesions, sores or ulcers on the body,
reddening at the base of the fins and the vent, loss of appetite and
darkening of coloration are all symptoms of infection. Ulcers may be
secondarily infected with fungus. In very acute disease outbreaks,
there may be very few obvious external symptoms.
TREATMENT If fish is still feeding, offer a full
course of medicated food (you can soak the food in the antibiotic
solution before feeding). Feed all fish in the tank with the same
food. If the disease has advanced fish are likely to refrain from
eating. In this case isolate the fish and treat with nifupririnol
(0.1-0.2 mg/liter, continuous bath for up to 5 days, may need
repeating) or, if unavailable, with antibiotics or a similar
antibacterial. Larger fish may be injected with a suitable
antibiotic and topical antiseptic should be applied on lesions.
Adding salt may help the osmoregulation of the stressed fish.
PREVENTION Find and eliminate the causal factor.
(Hole in the Head)
- caused by Hexamita
Protozoa parasites which are probably endemic in all populations of
wild Discus species, and even in tank-bred specimens. Usually
affects cichlids such as discus, angelfish, oscars and gouramis.
SYMPTOMS Small, whitish/greyish/or creamish
"worms" crawl out of head region of Discus family fishes.
Unless the infestation is massive and/or secondary bacterial and
fungal infections develop, the condition is rarely terminal but very
unsightly and may cause infestation of other fishes in system if
parasites are allowed to reproduce. Hexamita often exists as a low
level infection of the intestines. The onset of the disease may be
due to various factors (see precention).
TREATMENT Change 25%-33% of aquarium water for treated
rainwater or deionised water or tapwater (=decending order of
preference). Treat with dimetridazole (5 mg/litre, continous bath)
or metronidazole (7 mg/litre continuous bath). Metronidazole is not
absorbed through the gills, therefore in order to be effective the
fish must still be eating. In non-eating fish the drug will protect
the other tankmates and eradicate the pathogen from the water column
but will not treat the fastening fish.
PREVENTION Low oxygen levels, overstocked tanks,
unhygienic conditions, changes in temperature and poor diet are all
factors that could trigger this disease.
Caused by the coelenterate Hydra.
SYMPTOMS Hydra have a small, stalklike body, which
ends in up to ten long, slender tentacles. The tentacles have a
battery of stinging cells which Hydra uses to capture its food
consisting of small crustaceans, invertebrates or even small fish.
Although the size of Hydra may reach a length of up to 2 cm, it can
compact its body.
TREATMENT Improving the general hygiene of the tank,
avoiding overfeeding and regular tank maintenance may moderate the
build up of Hydras. Some species such as the three-spot gourami, and
the paradisefish will consume large numbers of Hydra. Raising the
temperature to 40 degrees C (after removing all the fish) is quite
effective. Hydra is also sensitive to salt. A salt percentage of
0.3-0.5 % is effective to control Hydra.
PREVENTION Improved general hygiene in the tank.
Parasites (see Worms
in the body cavity)
multifilis (ICH, white spot disease)
by ciliated protozoan (Cryptocaryon irritans
in saltwater and Ichthyophthirius
multifilis in freshwater tanks). May be
caused by non - irradiated livefoods. May be accompanied by other
skin and gill parasites.
SYMPTOMS Small, pure white, clearly-defined spots /
cysts (about 1/4 - 1/2 diameter / approximately the size of pinhead)
appear on body, gill AND finnage. (CAUTION: do not confuse
with same-sized GREYISH-WHITE, blurred-edge spots appearing on
finnage only). Some cysts may join together and form irregular white
patches. If untreated, spots slowly (6-24 hrs) advance to cover
whole body/finnage area. Heavily infected fish may look as if they
have been sprinkled with salt or sugar grains and they may scratch
against rocks and gravel and show increased gill movement. Fishes do
not show early sickliness and may even continue feeding lightly.
Secondary bacterial infections are common. Ichtyophthirius has a
direct fish-to-fish cycle and thus can build up quickly in the
limited space of an aquarium.
TREATMENT Carry out a 25%-40% partial water change and
treat immediately with appropriate medicine. In very hard water the
treatment should be used twice daily in the early morning and late
at night. Since the protozoan, while attached to the host is immune
to treatment, this has to be aimed against the free swimming stages.
Raising the water temperature to 32 degrees C (if the fish can
tolerate it) for a few hours every 2 or 3 days may be effective.
Since the disease is spread very easily it is recommended to treat
the whole tank instead of individual fish. You
have to keep in mind that this disease can devastate a tank in no
time. Ichthyophthiries multifilis cannot tolerate sodium chloride
levels higher than 1 ppT (parts per thousand or else 100 gr / 100
liters). If your tank inhabitants don't have a problem with salt
than this is the treatment of choice. I have tried it with excellent
results and no losses. Since I was keeping Madagascan cichlids when
the problem appeared I raised the sodium chloride concentration to 3
ppT over a period of 24 hours (1 ppT / 8 hours) and set the
temperature to 31 C. I left the temperature at this level, increased
aeration to its maximum and treated the tank for 15 days. You have
to keep in mind that although the visual signs on your fish may
vanish after 5-6 days at most (under these conditions) parasite in
its free swimming stage may still be present in your tank and lead
to a new cycle once you stop the treatment prematurely. I personally
think that 15 days is a safe duration for this treatment.
PREVENTION It should be stated here that most workers
in the field of fish pathology believe that these protozoans are
present in all bodies of water and in a resting (latent) state
within most fishes but only become active when fishes are exposed to
stress or otherwise weakened. It is believed that the protozoan is
introduced in a set up tank through new and not quarantined
acquisitions. It is always wise to quarantine your fish for four
weeks and use a white-spot remedy during this period. Washing newly
purchased plants under running water may also protect your tanks.
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