Comet Goldfish with small red marks/streaks

[Stef]

Water Parameters:

• pH   7.2
• Nitrates  50
• Hardness  300
• Nitrite   0
• Ammonia   0
• KH/Buffer   120
• Water Temperature 72F
• Above params from CoOp test strips

This afternoon while feeding my pond fish, I noticed one has some red streaky bruises on his face and body. These fish are in a holding tank in my basement waiting for steady temps to go back outside. 
There is a piece of driftwood that has some stems that jut out. I wouldn’t say they’re sharp but they are branched out. 
There is one large koi (9 inches) in with him and the other comets. There is no aggression that I can see but the koi can really throw his body around and makes waves when food is coming. The holding tank is a 40 gal breeder but is their temporary home. They’re all going outside to a 150 gal stock tank in my patio in two more weeks.  
 

Does it look like bruising or something more nefarious?  The affected fish is acting normal and eating normal. 

[Colu]

It could be caused by an injury but a couldn't rule out a bacterial component I think it would be worthwhile doing a course of kanaplex and add a small amount of aquarium salt 1 table spoon for 10 gallons@Stef

[Stef]

Hi @Colu things progressed for the worse and all fish seem affected with various conditions. I’m not sure if I should switch up meds as I’ve only gotten one medicated feeding of Kanaplex. 
 

All fish have clamped fins and I’ve seen two flashing against the glass and substrate. Two fish are hanging out vertically alongside the heater and seem to gasp at surface.  The koi looks like some ich or white spots on his tail but the spots are not bright white or pronounced. 
 

I have on hand Expel-P, ParaCleanse, Maracyn, Ich-X, KanaPlex and Metroplex. I’ve only used the kanaplex mixed with soaked pellets once. 
 

No changes to the water params, they are same as above but I can do another water change prior to treating the water column if you think that’s next step. 
 

• pH   7.2
• Nitrates  50
• Hardness  300
• Nitrite   0
• Ammonia   0
• KH/Buffer   120
• Water Temperature 72F

[Colu]

Looks like ich on the tail fin what I would do is start treating with ick X and aquarium salt 1 table spoon for 5 gallons as ich causes massive electrolyte loss and salt will add back in essential electrolytes do a course of maracyn in food feeding a small amount twice a day for 7 days kanaplex isn't very effective in food as very little of the medication is adsorbed by the intestinal tract  in this instance maracyn would be a better option and add an extra air stone during treatment @Stef

Edited April 11 by Colu

[Stef]

Happy to report all fish recovered and responded well to treatment of Ich-X and Maracyn in food. No more flashing or vertical bobbing. White spots and bruising are gone too. All vigorously swimming and eating. I think I’m going to co to us treatment for a few more days. Today is just day 5 of treatment. 
 

Thank you @Colu for the spot on diagnosis. I was really worried for these guys and the end of my pond season. 

[Stef]

Todays pictures. 

[Colu]

Good to hear they made a full recovery