Help, Fish Has Fin Rot Disease

[rony_roy_14]

few days back i noticed white spots on my red oranda goldfish.  my LFS told me to use thermostat.  i did the same and that fish died.  after that i noticed the same on my red tail shark.  i guess it's suffering from fin rot disease.  i am also putting a picture of the shark.  i dont know how to cure it and keep my other fishes safe.  please help me. 

 

[Meeresstille]

I think your fish is suffering from 2 illnesses if not 3. Ich looks like the fish has been sprinkled with salt, and I see such sprinkling on your fish. Then there is fin rot and possibly a fungal infection with the white-ish splotches on his body. 
 
There are medicines out there for ich treatment, or you can increase the temperature in your tank in addition to adding salt. You will need to treat the whole tank since the whole tank would be infected with ich.
 
The salt may also help the fin rot, but in your fish it has already gone pretty far, and at this point would need antibiotics. I don't know much about medicines myself but something that I have been reading about being often recommended is Kanaplex. It may also help with the fungal infection. I don't know if Kanaplex can be used at the same time as the heat-salt-treatment, you may need to find a medication to treat ich that is safe to use with Kanaplex. Never mix medications unless it is stated that it is safe to do so!!!
 
Can you also give us some information on how big your tank is, how many fish and what kind of fish? How long have you had them, how often do you change the water and how much each time? Have you added anything new lately to your tank that may have brought ich into the tank?

 

[rony_roy_14]

at first, thank you a lot meeresstille for ur reply.
 
i have a 100 gallon tank.  presently i have a carp, a couple of fishes i dont know the name, so adding picture of it.  i have had all these fishes for nearly a year until recently i introduced two goldfishes.  i guess those were already infected and brought infection to my tank.  cause those two also died.
i change nearly 75% water after every 2-3 months. 
 
i changed water yesterday, and as its winter time here in india, so aquarium heater is always on.  i measured that water temperature is between 26-28 degree celcius all the time.  so i guess temperature is not an issue.
 
the problem regarding treatment is, those medicines or aquarium salts are not easily available locally.  i showed my LFS my fishes and his only prescription was using of aquarium heater.  when i asked about any kind of fungal or bacterial medicine, he denied this.

 

[Meeresstille]

You probably are right, the goldfish may have brought the illness to your tank. 
Goldfish don't really like such a warm tank either which may have been partly responsible for their deaths.
 
For the heat salt treatment you can use regular table salt. Kosher salt would be better since table salt has anti-caking agents added, but it is not something that will be an ongoing thing for your tank and eventually with water changes they too will get removed. 
 
Your water changes are not nearly as frequent as they should be, sorry. Most people do weekly water changes, anywhere from 30 to 50%, depending on the bio-load (size of tank and size and amount of fish and other critters). 
 
Salt can help with fin rot too, just make sure you go slow in raising the salinity of the tank to give your fish time to acclimate. Your tank is pretty much up there in heat already at 28 C.
Here are two good articles on this:
http/www.badmanstropicalfish.com/forum/index.php?topic=1024.0
http/www.badmanstropicalfish.com/forum/index.php?topic=1285.0
 
It's a bit of a long read, but it had helped me when my tank had ich. I hope you will soon see improvement.