I've often wondered this, thought I should ask the people who are most likely to know (from experience)! I've got two goldfish, nice little Bronze guys, they've always stuck close to each other, often foraging on their own, then running off to find the other one and swim close for a while. They seem like best buds, bumping each other, taking turns to overtake then fall behind, it's like watching two give year old boys playing. I have always loved Shubunkins, as a kid my favourites in our overcrowded tank were a White and orange fantail and the Shubunkin. Now that my goldfish are in their own tank, I'm toying with the idea of getting a Shubunkin (or, I guess a Calico is better suited to an aquarium?). They're in a 29G, which math says is just right for the two, but since they're only young there is plenty of room for another friend, keeping in mind I'll be moving house at the end of next year and will plan to find a bigger tank for them when I do. To my question, I have wondered whether, seeing as these two have such a close relationship, will an addition be perceived as a threat? A third-wheel, to be shunned? Or welcomed to the party with open fins? I know the general answer is 'try it and see', but I'd love to hear from goldfish lovers with experience in adding an odd numbered fish into an already tight friendship. Thanks, looking forward to hear the thoughts!