if you want the fish to swim in an endless loop while something else is happening on the scene you will need to make a looping command.
I haven’t tested it so i am sorry if I made a typo - basically, you need 2 separate loops one for the scale and one for the shift…because the shift happens in time and the scale immediately I added the same command for scale after in time to create a pause for the time set fish moves to the other side.
&overlay GOLDFISH scales to 0.172 0.172 in 0 THEN overlay GOLDFISH scales to 0.172 0.172 in 14 THEN overlay GOLDFISH scales to -0.170 -0.170 in 0 THEN overlay GOLDFISH scales to -0.170 -0.170 in 14 loop infinite times
&overlay GOLDFISH shifts to 185 287 in zone 3 in 14 THEN overlay GOLDFISH shifts to 185 287 in zone 3 in THEN overlay GOLDFISH shifts to 258 334 in zone 3 in 14 THEN overlay 4972643041673216_GOLDFISH shifts to 258 334 in zone 3 in 0 loop infinite times