Hi there, im new to the forum, just worried about my goldfish.They ve been living in a two foot tank for about twelve months ,and have grown preety big so i thought i would get them a bigger tank.Last week i moved th. em into a four foot tank , i only have four fish so thought this would be better for them, unfortunatelt they dont seem to be happy at all, they are staying mainly on one side, venturing out occasionally and dont seem to be as interested in food, what is wrong with them, im seriously thinking of putting  them back in the smaller tank where they were much more lively. Please could someone advise xx 

hi ther thanks for re[plying , i will certainly do some water changes and theres nothing in thtss harmful for them ,i did everything right its horrible seeing them miserable x

Hi summertime, good news , been to tropical centre today had the ph level done , it was extremely low and the fish were not getting any oxygen , treated the water and they are back healthy now , thank u so much for your help xxx

i think a bigger tank is better, they will have more room.. they probably just need
time to adjust to their new home

hope i helped
xxx