Balcony fishie went for walkies

I underestimated my new goldfish. Day Two in their ingenious passively-filled new pond, and they decided the in-flow pipe for water was a good place to hang out. Then merrily they swam away from their pond, into the downpipe, and....
Well, the didn't come home that night.
I kept running to the garden downstairs, to check for something flapping and golden. Nothing.

One whole day fishless and perplexed, and the next day, they are back, swishing around like there is no tomorrow. Which would'nt really worry these rascals at all.