I recently had a bout of ich in a few of my fish and put them in a quarantine tank. My roommate too his fish back out after they hadn't shown any signs of disease for nearly two weeks. The only fish left is one tiny oranda. He seems fine until I try putting a carbon filter back in. He immediately stops swimming and hides beneath the filter. He has no external manifestations of disease and acts completely fine when the filter is removed. I have continued treating him for ich and am really not sure what to do to help the little guy.

Hi Fishchick! Welcome to KoKos! Could you answer as many of the questions in the white box at the top of the page as you can? This will help the mods to better understand your situation. Thanks!!!

Oooops, sorry. I am all out of test strips, but expect them any day now. The quarantine tank is ten gallons and has been going for about four months. The filter is an Aqueon (a thirty gallon filter). With the ich treatment I am using the instructions say to treat every third day changing half of the water before the treatment and then again after 24 hours. There is one fish in the tank an he's just over an inch long. The additives and conditioners I use are Amquel plus, Novaqua, and top fin conditioning salt. I feed him Aqueon goldfish granules and occasionally some freeze dried brine shrimp (he refuses to eat vegetables of any kind). He had a badly ripped fin when I got him, but it appears to be healing despite everything.

Hi Fishchick. Well, as I'm kind of a beginner at this myself, I really can't answer your question about why putting the media back in your filter would cause your goldy to hide, but I did just want to share the little that I do know. Filtrations should be 10x the size of your tank and so, for a 10 gallon tank you should have a 100 gph filter. Also, using Amquel can give you false readings on your ammonia tests, so I, personally, would suggest not using that. And, also, it is my understanding that they suggest not using salt on a regular basis as it can cause the fish to retain salt and fluids. It's also my understanding that filter media will remove meds from the water, so if you are still treating, you probably shouldn't have the carbon in the filter. My goldies hate veggies too, except for baby food peas that I've mixed a little brine shrimp with and frozen and then feed in little pieces. But, they do love some fruits such as tangerines, oranges, kiwi and strawberries. I guess they like sugar just like we do! One thing though, if your readings all test good and your goldy doesn't show any signs of disease, is that they do tend to be a social fish and if your fish was with some other friends and is now alone, maybe it's just kinda lonely. That said though, a 10 gallon is too small really to give him a friend......

What I would suggest is do a 100% water change for your fish. If it does have ich, then that an be treated with aquarium salt and some heat. Therefore, the other meds are not necessary. Second, I would suggest putting a filter in the 10g that your fish is in. If the filter for the 30g is too strong, then consider getting a filter that only turns over 100gph. Tetra Whisper filters are very quiet and should not scare your fish. However, your fish needs a filter regardless of if he is sick or not.
Also, you need a water test kit. I would not use strips as they are very unreliable. The API Master test kit is a good one.
What size tank and how many fish do you have, other than the 10g that your fish is now. In other words, what enviroment did this fish come from before you Qted him in the 10g?
Also, you really shouldn't use salt in your tanks unless treating a fish for stress or sickness.
Some pics would be helpful and also, the water params. Post back when you can!

Thank you for all of your help, but my little Oranda has joined that big pond in the sky.

Sorry your little fish didn't make it!