I've had a black moore goldfish for 5 years. I just recently brought him with me to a new city and he's temporarily in a five gallon aquarium. Originally he was in a 30 gallon aquarium with other fish (that is still with my parents) but he was getting bullied, so I brought him with me. He's been fine, and looked a lot healthier, but lonely. I decided to get him a baby black moore to keep him company.
I got the new fish from petco (I know bad idea.) When I went to look at them, I pointed out that one looked sick, and the guy said don't take that one, take this one. (Normally I would realize that if one fish was sick, the aquarium was contaminated, but I was in such a rush, it didn't cross my mind. I put the little fish in the tank and watched them together for a day before I went away for the weekend. They both looked happy, and the new one was pretty active.
When I came back, the little fish was covered in white spots. Not like ich. It looked like his entire body was covered in cotton or he got snowed on. I panicked because he looked like he was going to die any second and moved him into a tupperware container (I didn't have another aquarium) I instantly went out and bought a 2.5 g hospital tank, filter, and heater. I continued to treat him with pimafix, and the guy at the aquarium store (not petco) agreed this was the best method.
I watched him for a few hours, and the filter current and air stone made too much current for him to swim against, and all he wanted to do was lie inside a leaf, where the next day, I found him dead in that spot.:/
At the aquarium store, the guy suggested not treating them together as I wouldn't want to medicate my other fish unecessarily.
Originally when I added the new fish, I added a bit of pimafix and melafix to the tank along with some beneficial bacteria and aquarium salt, but I feel like I should have kept treating my older fish. Today I noticed he was very active. Since the other died, he's been getting a pimafix treatment everyday, just in case. I wasn't taking any chances. However, he is not normally very active, and I'm wondering if he feels itchy...
I did a 25% water change, removed the filter (I didn't have a spare and didn't want anything holding onto something potentially harmless. I removed the live plant, and plan to keep up with the pimafix treatment.
However, any ideas, or advice would be so appreciated. I love this fish and I couldn't forgive myself if he died too.
If you have any idea what this disease may be, please share! (The guy at the aquarium store thought it was ich over the phone, and when I showed him a picture he said "oh wow. I have no idea what that is."
If you need a picture of the fish while he was infected, I can post it.