hi, I currently have 2 180 litre tanks with 1 fancy goldfish in each. Both males but one is a real bully so I have had to keep them separate as he chases the Blackmoor I have constantly. They are both around 3 years old and about 5 inches. Both healthy and in good condition. I'm wanting to cut down my tanks as I also have a 100 litre tropical tank which I am wanting to upgrade into one of the 180s.
I have tried to rehome the fantail but can't find anyone to take him. I even offered the tank free with him to guarantee the right size tank.

So the only solution in can think of is to get a much larger tank for the 2 boys and dividing it in two.

Any thoughts on that idea? And any thoughts on size? I was thinking 6 or 7 foot so they had enough swimming room each. If they continue to grow will 3 foot of swimming room be enough?

Thanks

Your suggestion of a 6-7 foot tank, divided in two, sounds an ideal solution - provided that the filtration works adequately throughout each section.

A 3-foot tank length is the minimum suggested size in the Caresheets available on this website, so the larger you can get, the better - ND Aquatics have a good reputation for their custom-made tanks if you have trouble finding one that "fits the bill".