Sadly, despite having set up and maintained a healthy aquarium, filled it with well-fed fishes, things do go wrong and disease will strike at some time or another.

Fortunately, most of the commonly encountered fish diseases can be diagnosed and treated fairly easily. Access to a good reference book is recommended.

DIAGNOSIS : There is no substitute for good old observation.

Most fishkeepers become very familiar with their fishes' behaviour and should be able to spot anything out of the ordinary. Things to look out for are loss of colour, out of character swimming actions, lumps, spots, pimples, fraying fins, trailing faeces, swellings, eye protrusion etc.

The key to curing fish disease is early diagnosis. Unfortunately, symptoms of many internal diseases do not show on the outside of the fish (or affect its behaviour adversely) until the disease is too far established for any remedy
to be effective.


White Spot - The fish is covered in tiny white spots and may scratch
                     against rocks.
Marine Ich - The marine equivalent of White Spot.
Velvet - Similar in appearance to White Spot but the spots are much tinier
             giving the fish an appearance of being dust covered.
Fin Rot - Not exactly a disease in itself but more of a secondary infection to,
               say, a split fin and the infection site is aggravated by poor
               water conditions. Treat the cause not the effect.
Fungus - Cotton-wool like growth on the fish's skin.
Mouth Fungus - this fungus like growth around the mouth is not a fungus but a
                        slime bacterium requiring different treatment to that for fungus.
Dropsy - The body swells up and the scales stick out at an angle.
Carp Pox - Waxy growth on the body on coldwater fish.
Lymphocystis - Cauliflower like growth on coldwater fish.
                       This seasonal ailment often self heals.
Swim Bladder Problem - Fish cannot maintain a chosen position in the water;
                                    may bob up or down or tumble head over heels.
                                    A common ailment in Fancy Goldfish.

TREATMENT : If in any doubt about a fish's condition then isolate it
                         immediately into a separate treatment tank.

                        Use as much of the original aquarium water as you can if you
                        have to set one up in a hurry, otherwise set one up as closely to
                        the main aquarium's water conditions as possible.

Treatments range from adding medication to the whole aquarium, giving individual fish a medicated 'bath' in a separate treatment tank, using medicated foods, to injection and perhaps surgery on the fish whilst out of water under anaesthetic.

Whilst many common ailments are cured by 'off the shelf' remedies, sometimes antibiotics are required and these must be obtained through your veterinary surgeon.

Basic treatments such as medicating the aquarium or giving the fish a separate 'salt' bath are well within the capabilities of the average fishkeeper.

If you decide to treat the fish in the main aquarium bear in mind the following:

Extra aeration should be used, as medication often consumes more oxygen.
Remove any carbon from filters as this will remove the medication
from the water before it has a chance to do its job.

Treatment for disease in marine tanks is difficult as the usual copper-based remedies cannot be used as these will kill any invertebrates present.

© FBAS 1998 RCM/RDE            Aquarium Management Care Sheet 6 1/1

                                    Download this complete Care Sheet