I combed the internet hoping to find a similar case to my new sick goldfish. I went to the petstore and couldn't help but "saving" this little guy who had some beginning symptoms of fin rot and one red spot at the base of his top fin. At home, he was in my hospital tank which is a 10 gallons tank (30-40% water change daily while cycling it with Seachem Stability and Prime). He was swimming normally and eating normally for a goldie yet I medicated with 8 teaspoons of aquarium salt. Two days later, the red spot disappeared from the base of his top fin and was framing his mouth. He was now having a long red spot looking like a moustache. Eating and breathing normally. Then, the next day the red spot was gone and red streaks appeared instead on its tail fins. I did a massive water change figurimg it could be ammonia poisoning and primed it too. Today I bought Tetra Parasite Guard and am stating this treatment... Any suggestions for my sick goldie? I really am new to sick fish since my goldies have always been healthy. I really wanna save this lil guy!! Thanks for any advice.
Note: It really makes sense to me that my fish is dealing with a Costia parasite. I'll try to take a clear picture tomorrow!