ok first the situation. i have a cory thats about maybe 1 yr old. it has not had any prior problems but when i came home today she was swimming in place in one of the corners bobbing up and down to get air. after a good 10 minutes she setteled down to the bottom and hasn't really moved much since. physicly she looks ok EXCEPT for her gills look odd...like theres some kinda piece sticking out. it looks to big to be a parasite though and its not really inflamed. i have a picture that i'm going to post that has a pretty decent shot of the gill. all the other fish includeing the other cory are acting healthy and fine.
(click on the thumbnail for a much better larger image)
i just have done a 50% water change just now and cleaned half the gravel
tank stats BEFORE 50% water change
20 gallon tank
2 mechanical/carbon/bio filters
fish in tank
3 zebra danios
1 bushy nose pleco
1 weather loach (dojo loach)
1 checkered barb
2 cherry barbs
1 fish we can't identify looks kinda like a bloodfin tetra but doesn't have red fins, just underside.
various live plants
ok, the various levels in the tank were not ideal before the change
nitrates - 200+
nitrites - vitually 0
ph about 6.0
weve had the ammonia and nitrites under pretty good control but we can't seem to bring down the nitrates or bring up the PH nomatter what we try
she seems to be moveing around more since the water change but her gills still look odd. maybe the gill thing is my imagination. what do you guys think?
any help with the Cory or the tank is appriciated