Interesting thread. It mentions both pathological and non pathological causes of black spots. OP, how are your clowns now and did you read through the thread @Morti shared?There is an old thread here with a few ideas
Mysterious black spots on clown loach
I was looking at my two clown loaches thee about 7-8 cm in length and the only other diesieses they have had is ich but that was a couple month ago ,they are well fed too ,but anyways they are more like black sploches and there over lapping each other,some are dark and some are light but there...www.monsterfishkeepers.com
Black Spots on Clown Loaches
- Thread starter Cheesyclop
- Start date
I had some on mine when I changed lights then it faded, maybe it’s just melanin skin reaction.
unfortunately the OP of that discussion did not post pics.
I was curious regarding the back story on this piece of driftwood that was added right before the spots showed up on the loaches. Snails, and snail eggs, are both easily introduced with driftwood, and a known cause of the transmission of black spot disease.
I’ve read through all the links to other posts. I can post more pictures later. They seem to be doing better with the increased water changes but it hasn’t gone away completely. They have stayed pretty active and eating the whole time so I’m not sure if it’s just a cosmetic issue or what.
I bought the drift wood second hand off a marketplace type app. I tried to clean it the best I could but you never really know. And to go off some of the previous replies I definitely don’t think it has anything to do with them sparing. I’ve seen the grey out before but recently they have been pretty colorful and all getting along