So, I've got 8 goldfish of various sizes in my 1000 gallon pond. They have all gotten along just fine and survived the winter like champs. Over the last month or so, I've noticed that 2 of the fish have taken up very specific hiding spots (wedged in between rocks). They don't tend to come out during feeding time or really any time (I've been out during the day and at night, both sneaking up on the pond and making plenty of noise). It is my biggest one (8") as well as the smallest one (3"). Is this something I should be worried about? On the few occassions I have seen them, they seem perfectly fine and will eat a little bit. But I only see them maybe once a week, while the other 6 are out constantly. The fish all have a cave they can use to hide from predators, so I'm not sure what would cause them to do this. I didn't think much of it at first, but after a month of this, I'm starting to become concerned. Especially since we've finally had some warm weather for a week and a half.