Last week a tan ick like disease showed up on half of the clown plecos in my 90 gallon. It is only on 4/8 of them and has not affected any of the 60 panda cory's, bristlenose, SAE, or my schoutedeni puffer. The clown pleco's were all fat and happy when they entered the tank after 2 months of quarantine with med trio and 3 rounds of deworming. They've been in the tank for almost 4 months before this showed up. Tank parameters are: Ph 7.6, ammonia/nitrite are 0 with 5ppm nitrates, Hardness 120ppm, KH 460PPM. Water temp in normally 76F but I bumped it to 80F. I used the med trio on the tank for the last week with no affect. The clown plecos are getting sunken in stomachs but only the ones with tan spots. Tank is planted so I've avoided salt. Thanks for any input or advice in advance. Any questions about tank or parameters I will try and answer.