They weren't being fed together, apparently a piece of watermelon got left outside I know I should've been more diligent about picking it up especially since its a high value treat for my corgi. They aren't fed together though, Tank is fed in his crate and Sherlock is fed in a different room and the bowls are picked up after feeding.
Have there been tiffs or is Sherlock a bully? Herding breeds can be pretty bratty.
Yes they've had a couple scuffles, but they broke up relatively quickly and no one was worse for the wear. Sherlock is definitely the instigator, she is a very typically bitchy female corgi.
My guess is that either Tank has Food aggression or Sherlock is tormenting him and a high value item/beginning maturity/patience running out instigated a fight where he had enough of her and let her know it. Because as others said this is a fairly unusual fight.
Tank hasn't shown any food aggression that I've seen, however I think you're right about the high value/beginning maturity/patience running out. Sherlock has a dominant personality, and I think Tank is starting to test that, and I don't think he wants to be bossed around by a dog half his size. I agree, I'm still surprised by the level that fight reached.
I just keep going back and forth, I don't know if this is salvageable. Sherlock, bitchy as she can be, doesn't deserve to live in a house with a dog that is going to try and kill her. On the other hand, if this is a matter of training, crate and rotate for a few months while hormones level out/he gets fixed but eventually could be a peaceful household I'd like to try that.