The Bodhisatta was once a fish. He and two companions swam downstream from the wilderness and came to a place where humans lived. The Bodhisatta knew it was dangerous for them to be there and said they should return, but the other two fish were lazy and chose to stick around.
After three months had passed these two fish got caught in a net. The Bodhisatta swam and splashed the surface of the river in front of the net and then did so behind it, making the fishermen think the two fish just snared had broken out. So they lifted out one corner of the net to repair it and the two fish were able to swim out to safety.
In the Lifetime of the Buddha
Two aged disciples of the Buddha spent the rainy season in a forest. When it was time to return to the monastery they packed provisions for the journey, but kept delaying their departure. They did this for three months before finally setting off. When they arrived, they admitted to being lazy and the Buddha told this story of their earlier births as the two lazy fish so everyone knew they had once before been reluctant to leave their temporary dwelling.