What's on my trigger?

[gregzz4]

Near as I can tell in the pic it looks like damage and missing scales/skin. If I'm right the pattern doesn't look like a disease, but don't quote me

Whether I'm right or not, keep your water quality up (water changes enough to make a difference - 25 to 50% at a time) and feed well. No ammonia or nitrites and low nitrates

If it's a healthy fish it'll heal on it's own given a clean environment and lots of nutrients