I have 4 SILVER DOLLARS (TROPICAL FISH) and need to know WHAT FRUIT OR VEG THEY LIKE?

Could loads of people let me know what sort of fruit/vegetables SILVER DOLLAR fish like to eat as ive been feeding them flakes and bloodworm and they really like it….BUT IVE BEEN TOLD THAT THEY ALSO NEED A FRUIT/VEG DIET MOSTLY, BUT WHEN IVE PUT CUCUMBER IN THEY DONT SEEM THAT BOTHERED, ALSO THERES SOME KIND OF LETTUCE THAT THEY LIKE BUT IVE FORGOT WHAT TYPE?????????????…………PLEASE CAN ANYONE GIVE ME IMPORTANT NAMES OF THE FOODS IN WHICH ARE AVAILABLE IN THE UNITED KINGDOM INSTEAD OF AMERICAN TERMS????????????
PLEASE HELP

Any spirulina based flake or pellet will be all they need. You will pollute your water if you are not careful with the natural foods.