Skin excessive sliminess
Skin shows mucous and slime far in excess of normal.
Gills have excess mucous
Obvious slimy mucous is oozing from the gills of the fish.
Abnormal swimming - streaks
Fish swims in short bursts, then stops.
Grey/white spot around head.
Around the head area is a large grey or white spot.
pH water low <6.5
A few species of freshwater fish (Discus) can tolerate lower than 6.5 pH.  If lower than this and problems, suspect this a possible cause.
Breathing at surface
Fish stays at surface usually at an inclined angle and breathes or sucks air.
Respiration rapid
Fish is breathing very fast, much faster than is normal.
Subepithelial petechiae
Small bloody red dots or effusions, evident below skin.
Loss of balance
Fish keeps falling from its attempted swimming pattern.
Sits on bottom
Fish sits still in upright position, on the bottom of tank or pond.
Hiding abnormally
Fish hides behind rocks or suchlike, appearing seldom if ever.
Listless and lethargic
Fish moves very lazily in water, much less than normal, lacks interest.


Too low pH. Can be caused by unsuitable water supply, reductive processes which take place in the tank/pond, pollution of the environment etc.


Can be remedied if the cause is determined and can be treated. In tanks where there is control of the environment treatment is possible. In ponds/cages it is much harder. Outlook is excellent if pH can be raised.


Please login to see the treatment information.


Dr. Bullock, Graham L.
US Fish & Wildlife Service
Nat. Fisheries Res. C. 

'Pete' Bullock, one of the founding luminaries of Fish Pathology 

passed away  in 2011
March 6, 1935 – January 8, 2011


There are 9 disease pictures available. Please log in to see them.

Login has failed
Login has failed
Don't have an account? Register here


There are 5 disease videos available. Please log in to see them. Protection Status