I have a 1000 gallon pond, very well filtered and aerated, I am not new to keeping fish, I have kept a happy pond for over 15 years now. I have a mixture of fish, Koi, Shubunkin, Goldfish. Tonight 3 of the goldfish were chasing constantly one of the others. They seemed relentless and the poor thing seemed exhausted and was tirelessly was trying to avoid them. Was it mating perhaps? I have removed it now and put it in a quarantine tank, was this the right thing?