I've always trusted the pond shop owner in the past, and I would have no fish left alive if it weren't for him. He looked at pictures of the fish and listened to my description of the symptoms. The medication says it's very low key and safe, and won't affect bio filtration. Pond has been cycling for 3-ish weeks now, so still very new. The medication also treats fish lice. As for costia, they definitely have some symptoms, but are not lethargic or respiring heavily.
How did you ever make out with the Cyropro ? If you find no results and I'm not sure you will, check this out! You didn't have anchor worm which is what I believe you're medicating for with Cyropro.
I was re-reading your posts and symptoms and Trichodina popped in my head. You might want to read this.
Trichodina in Koi Fish
The Trichodina koi parasite is another of the microscopic pests that sometimes attack our pet koi fish. Generally speaking, Trichodina alone will not kill your koi; rather it damages the skin and gills of the fish which can lead to bacterial infections. However, these secondary bacterial infections are notorious for death loss in koi collections. Instead of piercing the skin to locate and feed on blood like so many other parasites, the Trichodina dine on bacteria in the pond water. It uses the koi as merely a place of residence, all the while inflicting damage to the skin and gills of the host as it spins and gyrates continually. The constant revolving motion is extremely irritating and causes damage to the fish’s protective coating, the slime coat. As the slime coat becomes compromised bacterial infections will take hold resulting in sores and ulcers.
If you are looking through a microscope at an organism that is round with tiny hairs radiating outward from its edge then you’ve discovered an adult Trichodina parasite. It looks very similar to the typical yellow sunshine on children’s artwork. Trichodina is saucer shaped and has tiny cilia, or hairs reaching outward. The cilia enable the parasite to propel its self around. The cilia are also used for suction to the host. Trichodina parasite is in constant motion, continually spinning in a circular pattern. With its constant revolving motion it can travel quickly all over the body of the host. Trichodina fish parasites are able to swim freely from fish to fish, too. Incidentally, Trichodina will also adhere to invertebrates and common amphibians such as frogs and toads.
These tiny parasitic organisms can even live in dirt or mulm that accumulates on the pond floor, or in an overly dirty filter. Trichodina parasite on koi is closely associated with poorly maintained filtration systems and poor water quality environments. Trichodina does not dine on your koi fish; instead it feeds on the bacteria in the water. Ponds with high bacterial loads provide abundant food and the ideal environment for Trichodina to flourish.
Trichodina parasites have a simple direct life cycle. They reproduce by binary fission, literally cell-splitting. This produces daughter cells that mature in a matter of days, will be free-swimming and eager to attach to a host within 24 hours.