Black/Brown on Yellow Lab fins.

[Marconis]

A week ago, I noticed a brownish/blackish mark on its left bottom fin, now today I noticed it on the bottom tip of the anal fin and two front fins. What could this be?

 

[Zagz]

Can you get a pic? Sometimes yellow labs get spots or patches of black, it's a color variation. It starts out with a fewt then spreads. I have one that got this and eventually got a 5 o'clock shadow, so now we call him Homer. As he matured it got more black. LOL If this is similar then it is normal.

 

[Marconis]

Unfortunately, I cannot get a pic just yet. Until I get my camera. It doesn't look much like your photo, but wow that does look like Homer!