Went to the lfs the other day and found a veil-tail betta with a sword-like extension. First thought was FREAKING COOL! Almost had my wallet out. Then my brain started working and I asked why I had never heard of swordtail bettas and why it was only regular price.
Ends up it had tail rot which created an unusual tail
I brought it and the other betta with NO tail to the manager's attention.
I'm glad to hear you handled it professionally. Too often you hear about people just yelling at the owner or manager rather than speaking to them about the situation like adults. I'm sure they appreciated it also.
I went to a Petco in Houston a few weeks ago, and if I wanted to bring the manager's attention to something like that, I would have had to tote nearly 30 cups with me to his office!