So here lately I've had issue after issue starting with ich, then a sudden death of my last Dwarf neon rainbow that was extremely healthy, the rainbow has had this for quite some time but here recently is gotten more red with looks like a pimple in the middle, I've never seen anything like it before and can't find anything on the internet about it except myco something or fish TB, she has no curvature side to side but there is a raise where this bump thing is, she eats like a pig, very active, not skinny very happy fish, but this is worrying me as I don't know what it is and how to treat it. Pics attached
Water parameters are
0 ammonia
0 nitrite
15 nitrate
Gh 5.5
Kh 6
Phosphate 1.5-2.0
Temp 79


