I have 6 Geophagus Altifrons which have been happy and healthy but where looking a bit thin, so I did a water change as per normal last Saturday and thought I might do a treatment for worms just to be safe. Anyway tonight I come home from work and all of the Geos are doing weird shit all over the show, vibration, flashing on the sand and driftwood staying still on the bottom. Some also have some welts on their skin not sores but like a lump.
I tested the water and found my water was 0.25 ammonia, 0 nitrites but nitrates are quite high like over 40.
I have done another water change to try and sort the ammonia and nitrates. Other fish in the tank seem fine. One good thing is the fish aren't looking washed out and still showing colour.
Would the worm treatment be something that could cause this?