So I picked up some thinBar SD and some of them appear to have these red spots between the face and the bar....at first I thought these were parasites but when I did some research I found that only males of this species get these?...is it true?
those guys in the pic sort look like the widebar but I could be wrong. I had 6 of the thin bar and noticed some would have that red on the side It would come and go never knew what it was but I had those guys for 5 years and never any issues with that red being there. My thinbars only got 5 inches in a 90 gallon that was lightly stocked with barbs, I have seen the widebars get 15 inches across.
Yes thinbar males get this red dimple bumps on there sides when they reach mature age. But I only seen it on others. My thinbar males do not have it. I purchased a small 3" male from my LFS. It had the distinct extra lobe on the anal fin identifying it to be male it also had lots of those dimples on its sides. But all my thin bars i had already in my tank were all bigger 4-5" no dimples and none showed yet any lobing on the anal fins. My males didn't start do develop the anal lobe on there fins until they reached around 6". That one small male I purchased after a few weeks in my tank the dimples disappeared and the lobe on the anal fin shrunk away looking like a female like the rest of mine. Not until it also reached 6" the lobing developed back in the anal fin.
My theory is the small one I purchased was stunted. It should of been bigger like mine but did not get lots of feeding and growth mine were receiving making he fish look more mature for its small size. I think my males will develop the dimples when they reach the mature age and they should be close to full grown size. 3" is not full grown size but may look mature cause it was getting stunted. I think I rescued it in time before that stunting stopped its growth.