Missing ventral fin

[Reaper]

Today, I was inspecting my tank and Fishbone Jr. (blue vt) it looked like he was missing one of his ventral fins. On closer inspection with magnifying glass he was missing one. Was he missing one when I bought him or did it go missing since, I do not know. I bought him young from Petco about 3 months ago. He was small but has grown into a big boy. He is active, lives in a planted 5gal fluval chi, heated 80-82 degrees, filter. 5 ghost shrimp tank mates.
Should I be worried? Will it grow back? No obvious other signs or symptoms.

[tpocicat]

Some betta fry just never grow ventrals, or in your case one ventral. Nothing to worry about. They can still swim fine and live healthy lives.