Black line on Index finger nail. 1 month

Dear Team, I am 35 years male and taking anxiety related medicines since last 5 years. I am feeling good so far with current meds and counselling . My current tablets are Reway Five( Multivitamin), Betacap 20, Pexep CR 37.5, Lonazep 0.25 and Buspin. I am on this prescription since Dec 2020. Before that I was taking once a day Venlafaxin ER 150 Mg from 2018 Oct. I am going quite good on current medicines but I noticed one clear thin black line in my right hand index finger's nail since last 3.5 weeks only. I know nails tell a lot about human health. I have attached the pics of my nail with this post. Is this something alarming? I am taking healthy diet and ample sun light also. Could you please help me to understand this ? I didn't notice anything different in my health after this black line came but I am worried to understand this.