Passage Summary: Fish raised in 'fun' environments with lots to look at act braver when they get to the wild than fish raised in boring tanks. Because they are braver about exploring and eating new things, the author thinks they will live longer.

Conclusion: Fish raised in experimental, stimulating hatcheries are more likely to survive in the wild than those from traditional hatcheries.

Reasoning: Experimental fish show bolder behaviors, such as exploring new environments and trying new foods, compared to their traditionally raised counterparts.

Analysis: The argument relies on a significant 'Gap' between behavior and survival. It assumes that being 'bolder' and 'exploring' are actually beneficial traits in the wild. To find the necessary assumption, ask yourself: 'What if being bold actually makes the fish more likely to be eaten by a predator?' The argument requires that these specific bold behaviors do not decrease the overall chance of survival.