Hi Kasha. In my experience, Koi are not territorial but very social. Is it spring where you are? If it is, have you made any water changes yet?

Your's Koily, Lorraine

Big Red has been out and about and grazing with the others the last couple of days - I am so relieved. May not have to quarantine after all - whew. He was definitely stressed about something though, not sure what.

Mine are goldies - not koi - who are indoors over the winter. I moved them out early this year - mid March - and they all seemed OK until the new fish showed up a week and 1/2 ago.

I guess what Im curious about is if in the wild they would travel in packs or schools and be "bonded" to each other.... do they relate to each other as indviduals or is one fish pretty much interchangeable with another fish to them. When I first put the new ones in it seemed the 2 groups mingled a little but for a couple of days tended to stick together, old fish together and new fish together.

It's just interesting to speculate what if anything goes on in the fish mind. They are much more aware than I thought they would be.... they can distinguish between me who feeds them vs. my cat who wants to eat them.

Goldfish (even young ones) are like old fogies. They don't want anything to change. Since your fish have been together for years, they probably had no concept of "other goldfish," so the new arrivals were puzzling. But goldfish are very sociable and normally accept new arrivals as pondmates in a week or two. Based on my observations of my fish, some form close bonds with other specific fish, and others seem content with any companions.

I am sorry to report that Big Red is having some problems & is indeed sick -whether related to the behavior I reported here I don't know. He is not acting sick, he is out and about, swimming, copeting for food etc. - but now his body has swollen up - looking somewhat like dropsy although scales are not sticking really far out like some of the pictures Ive seen.. This is heartbreaking Wish I'd netted him and moved him into a hospital tank when he was hiding because now I can't catch him - will try partially draining the pond later today. Lesson learned: you know your own fish better than anyone - probably best to hospitalize at the first sign of trouble? What Im reading - if it is dropsy/ kidney damage, has to be addressed asap or once its too late nothing can be done...........

I hope everything turns out okay for him.