LOOKS like a possible regurgitation. Those are said to stink pretty good. Though I've had some pretty rank Blood/Short Tail poops.
BUT, runny stools are an indicator of parasitic problems as you are aware of. Would be worth having it checked out.
Why did he get a few small rats last week?
That could have been a cause of something, too much food too fast.
Also double check temps.
MIGHT try lowering hot spot to 85 or so.