Help! Unknown Illness

Hi I needed some input into a sick paradise fish that I own. He has been sick for about 3 weeks now and what ever it is it is slowly progressing. He lives in a tank approx 190 litres with 3 other paradise fish 2 silver sharks a black knife ghost fish and a couple of male guppies supprisingly all fish get on very well. I have the water tested on weekly basis through my local aquarium shop and has always been fine the tank has been set up for about 12mths. I have had this guy for about 6mths now and never had a problem with him until 3weeks ago I noticed a band of scales just behind his right pectoral fin almost seemed to be contracting that is the only way I can discribe it as they are not sticking out the following day he started hiding in the corner and not doing really well I started treating tank first of with Melafix and he improved slightly but the next day he seemed to go down hill very quickly he sinking to the bottom head first and was being attacked by the other fish I moved him into an isolation tank expecting him to die overnight. Suprises suprise the following morning he seemed to of recovered and was swimming arround showing no signs of illness except the unusual scales so I ended up putting him back in the main tank as he was getting very stressed. Since then he basically hangs up in the top corner of the tank next to the heater and very rarely moves from there he comes out to eat then goes back into hiding again. For the past 3 weeks I have been treating the tank with Melafix on a daily basis and have added in Promethasul once a week which was recommended. Over the past couple of weeks the band of scales on his body has approx doubled but is only on right side of his body they look like they are tightning up and about a week ago he developed what looks like shaggy scales on is face on the left side. I have taken photos of him to about every aquarium shop that I know gone through about every disease book with them and have not found anything even remotely like it the scales on his face look bacterial but the body has us totally confused. All of my other fish seem to be doing ok and show no signs of it. Please if anyone has any ideas of what this might be I am desperate for help as he seems to be hanging in there. I have attached some pics I hope they are clear enough for you to see any help would be greatly appreciated I hope someone might know what I am dealing with. Thanks

nebs said:

Hi I needed some input into a sick paradise fish that I own. He has been sick for about 3 weeks now and what ever it is it is slowly progressing. He lives in a tank approx 190 litres with 3 other paradise fish 2 silver sharks a black knife ghost fish and a couple of male guppies supprisingly all fish get on very well. I have the water tested on weekly basis through my local aquarium shop and has always been fine the tank has been set up for about 12mths. I have had this guy for about 6mths now and never had a problem with him until 3weeks ago I noticed a band of scales just behind his right pectoral fin almost seemed to be contracting that is the only way I can discribe it as they are not sticking out the following day he started hiding in the corner and not doing really well I started treating tank first of with Melafix and he improved slightly but the next day he seemed to go down hill very quickly he sinking to the bottom head first and was being attacked by the other fish I moved him into an isolation tank expecting him to die overnight. Suprises suprise the following morning he seemed to of recovered and was swimming arround showing no signs of illness except the unusual scales so I ended up putting him back in the main tank as he was getting very stressed. Since then he basically hangs up in the top corner of the tank next to the heater and very rarely moves from there he comes out to eat then goes back into hiding again. For the past 3 weeks I have been treating the tank with Melafix on a daily basis and have added in Promethasul once a week which was recommended. Over the past couple of weeks the band of scales on his body has approx doubled but is only on right side of his body they look like they are tightning up and about a week ago he developed what looks like shaggy scales on is face on the left side. I have taken photos of him to about every aquarium shop that I know gone through about every disease book with them and have not found anything even remotely like it the scales on his face look bacterial but the body has us totally confused. All of my other fish seem to be doing ok and show no signs of it. Please if anyone has any ideas of what this might be I am desperate for help as he seems to be hanging in there. I have attached some pics I hope they are clear enough for you to see any help would be greatly appreciated I hope someone might know what I am dealing with. Thanks
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I am not sure if this will help or not, but had a simular problem just differnt fish so here it goes....
I had a red irian rainbow that when got home was highly stressed due to low water level of transport bag (I know this has nothing to do with your problem but read on). Once in tank it was the red irian and a parkinsoni rainbowfish together...now keep in mind these are schooling fish....so i went ahead and treated tank for finrot as he was showing very bad signs of it from stress of xfer...for the next week or two he would swim around as normal and feed as normal as you said, but would hide up by the heater when was doing nothing else in the corner of tank...so thats where our situation becomes simular....the solution i found was adding a smaller red irian...since then he has not been hiding or acting this way...so question to you is...is your fish a schooling fish that likes the same of its own species? and if so how many and how much bigger are the others compared to him?

Looks to me like a bacterial infection under the scales. As for treatment I dont know as uk meds arent that great.

You do no bala sharks and black ghost knife fish need large tanks.
Now the scales get a magifying glass and check and see if you can see anything behind them, does it look like something is pushing them up, look for parasites, as parasites can cause bacterial inrfections on top.