Scratching...but No Whitespot!

[lordofthesea]

i've just noticed some of my fish are scratching on leaves and wood. yet not one fish has whitespot (ich). added to this, the presence of ich seems unlikely as i've been treating the tank with melafix and pimafix for the past fe days as a congo tetra had some fungus on his lip (it's gone now though). why are they doing this? is it the medication?

 

[Colin_T]

Melafix and Pimafix don't kill whitespot. But the scratching could be an irritation caused by the chemicals in the Melafix or Pimafix. Try doing a 50% water change and see if they continue to scratch.
Check the fish for any grey, cream or white patches on their body, particularly along the back. If they have this coloured area then they probably have something like costia, chillodonella or trichodina, which will cause scratching and need treating with something similar to whitespot treatment.

 

[mattbond]

do fish ever just scratch if they arent ill? because occasionally i see tetras and platies doing it, and i didnt get whitespot at all?

 

[Colin_T]

Fish do sometimes get an itch and rub against something to relieve it. However, if the same fish is regularly rubbing against things in the tank, then it probably as a skin irritation. Normally this is caused by a disease (external skin parasite like whitespot or costia), but poor water quality (ie: ammonia, nitrite & high nitrate levels) can also irritate the skin as can chemicals and medications.