I would not do another treatment of kanaplex over use can damage fishs organs it could be secondary parasitic infection I would do a water and start on ich X and API general cure
can is feed a variety of food hikari micro wafers and pellets and vaibra bites really good and good range of frozen or live food and keep really go good water conditions
It is only effecting my Columbian blue tetra I have not loss any x-ray tetra or bristlenose from same tank which is unusual if it were bacterial or parasitic infection
I have Malaysian trumpet snails in 50gallon planted tank they are good for agitation of substrate if have to many put some assassin snail in to keep numbers down