Looks like both fin rot and brooklynella on clown. The fin rot will be associated with bacterial issue which makes sense with brook. At the onset, fish may scrape up against objects, rapid respiration develops, and fish often gasp for air at the surface as the gills become clogged with mucus. Very quickly the fish will become lethargic, refuse to eat, and its colors will fade. The most noticeable sign is the heavy amount of slime that is produced by the fish that has contracted this parasite. As the disease progresses, a thick whitish mucus covers the body which appears on the body of yours. This will usually start at the head and spread outward across the entire body. Skin lesions can appear and it is not uncommon for signs of secondary bacterial infections to arise as which may explain the fins.
Most common treatment for this is formalin (quick Cure is an example). Typically a standard formalin solution is mixed with either fresh or saltwater in a separate treatment container. Initially, the fish is given a quick dip in the formalin at a higher concentration, followed by continued treatment in a prolonged bath of formalin at a lower concentration in a quarantine tank (QT). Of course, the longer the fish are exposed to the formalin treatment, the more effective it will be at eliminating this disease.
If a formalin solution is not available for immediate use, temporary relief may be provided by giving fish a FW dip or bath the same temperature as display tank. Even though this treatment will not cure the disease, it can help to remove some of the parasites, as well as reduce the amount of mucus in the gills to assist with respiration problems.
