we have a small garden pond and the weather is colder
A heron's stomach or what MarcThyme said.
Ask your pond supply what a heron net is, you may need one.
They are probably just waaaaay down in the bottom of the pond, resting in the mud to keep warm; in the winter, (even when a pond actually freezes over), there is still liquid water in the bottom that stays at at least 4C, which is warm enough for most fish. Because they are cold-blooded, however (meaning their blood-temperature is actually dependent on the temperature of their surroundings) , when it's that cold they slow way down, not quite like hibernating but close to it ... when the weather warms up again they'll be back!
you got jacked. Hide ya goldfish errybody
probably hiding under some rocks or water-vegetation, or maybe a cat ate them.
Cats tummy?
