Advice Please -My First Goldie,Thinks He'S Tropical!

[fishnovice]

Just adopted a goldfish. Yep another Pets at Home victim. Luckily owner realised 3inch goldie couldn't live in small under 18in tank with 6 other TROPICAL fish and rehomed him. Was planning to put goldie in coldwater tank but it's been brought up as a tropical. Can it be adjusted to coldwater? My plan is to get goldie used to the cold slowly
keep it in warm bedroom in unheated tank till Feb
move to colder kitchen in March
outdoor tank and eventually pond in summer
Would this work?

Also need ID -looks like a shubunkin (silver with black spots and red patches) but has a long forked comet type tail.Pets at Home sold it as a "fancy goldfish".. but then they also sold the same trusting person an unknown pleco species as a "bottom feeder" without warning about likely size. Poor plec is still only 2in after several months and may be stunted already, no bristles so not a BN

 

[aly_starh]

All goldfish are temperate fish found in cool streams, lakes, and ponds throughout Asia and part of eastern Europe, though all the specimens found in the hobby today are captive bred. Goldfish can be easy to care for, however, they do require some care. Given proper care and a good, healthy environment, goldfish can live nearly 50 years!

To keep a goldfish healthy, remember to provide them with plenty of clean, cool water.

Your goldifsh's temperature should never rise above 73° Fahrenheit, and ideally should remain between 65° and 68.

Whats the new tank size?

 

[fishnovice]

2ft, not ideal I know but only a temporary measure till he can be moved to 4ft tank and eventually pond. At least he's on his own not sharing with 6 other fish in a smaller tank packed with plants as before. No substrate so can do frequent (daily if necessary) water changes to ensure water quality is OK.

It's a lovely fish and I really want to do the best I can for it.How much food should I feed him? He's very greedy , possibly underfed competing with so many others for food before, though he looks healthy and isn't skinny.