Crusoe completely healed last week but now he is returning back to his sick conditions. However, his health worsened rapidly and he has become just as sick in one day as it took him three days to get the last time. I cannot figure out what is going wrong or what in the tank can be causing him illness.
Once again, Crusoe is heavily lethargic. He had appetite this morning but no longer eats. The pellets I thought he ate in the morning he actually spit back out. His fins/tail are all clamped again and he move rarely. He is currently laying at the bottom of his tank breathing somewhat normally but not swimming or moving any fins. He does occasionally swim around the tank but his movements are jerky and few.
However, this time I notice his eyes have changed. They are not cloudy or protruding, no signs of eye-related sickness that I know of. They are changing appearance. When I first got him he had dark eyes and their color was mostly undeterminable except when light hit at a certain angle, showing he has deep blue eyes. However, now a circle around his pupils can clearly be seen and the blue in his eyes is very easy to notice. It is not the fact that his eyes have color that bothers me but where he has color. The color only show just under his pupils on both sides and moves when his eyes move. I do not know if this is related or just fish-eye normal behavior but I find it strange.
I have some theories as to his behavior/health change.
Last time I placed him in a hospital tank and gave him one dosage of Jungle Parasite Clear. His health greatly increased and he seemed to recover overnight afterward. Although the instructions called for a second dosage in 48 hours, I noticed his slime coat appeared to be coming off so I stopped the medicine dosage, continued with water changes, and put him in his 5 gallon tank after a day of monitoring. I wonder if I should have given him the second dose now and if the problem came back because it was not truly eradicated.
My second theory is that carbon in his sponge filter is bad. I have heard recommendations to remove it but could not figure out how to and left it in. I have read some things suggestion that carbon can be bad for fish and cause illness, so I cannot help but wonder if that is the case. His illness appear right after I introduced the filter into the tank and he recovered outside its presence, so perhaps his return to the tank with the filter has caused this condition.
Finally, I saw that the day after I placed him back into his 5 gallon tank he managed to shred his tail. His water was freshly clean and I added a very small amount of aquarium salt to prevent infection. I have removed the decoration I believe tore his fin and replaced it with a new hiding spot that has no sharp edges at all. Could his tiny shreds (they were very minor) have gotten infected anyway? They have no change in color and have not gotten worse.
After the last time he was sick, I did a 100% water change and thoroughly cleaned everything, including the sponge filter under tap water in case some bacteria from the old tank water was harmful. He was fine until today. Ironically, he fell ill last Friday too.
I have been doing regular water changes, trying to get this cycle to start. I have had no luck and the water conditions have remained stable but not ideal. He has no nitrites and no nitrates, only ammonia which does not get above 25 ppm. I checked it before I did a SECOND partial water change today, finding that the ammonia level was between 0 and 25 ppm, so probably 15-20 ppm. I had done a 10% water change in the morning but after seeing his conditions were not improving, the second water change was a 75% change.
His temperature maintains itself at 78 to 80 degrees in a 5 gallon, uncycled (but I am trying) tank.
Does anybody have any idea? I have a medical tank on standby in case he is not better by tomorrow. He is floating at the top of the water not moving at all, only breathing softly, at the moment. He is still responsive but like last time he has a change in personality.
I am considering changing food. I wonder if it has gone bad or is contaminated with something. Other than that, I have no idea what to do. I do fear he will die if his conditions do not improve...