Looked in my small tank just now and horror of horrors!! The guppies were eating a piece of fish with skekton attatched (I didn't put it in there). Had a quick head count and one leopard dannio missing Poor fishy. Have tested water values and they are fine but should I do a water change anyway? The dannios have been in for over 4 weeks and the others look fine.
Yeah, most likely natural causes. I doubt the guppies attacked the danio. They're probably not fast enough to catch a danio anyway. Too bad though. Not a pleasant sight.