A robot disguised as a crocodile is helping scientists understand that mass fish die-offs serve a purpose.

It takes place out of sight of non-anglers, but fish stocking, or adding fish for the benefit of sport fishing, is a widespread practice in resource management.

Fish intelligence? Yes, many studies have documented the ability of fish to learn from their environment. Fish exposed to a more complicated environment have an edge in learning.

Every year, thousands of American eels make an amazing migration from their freshwater homes into the Atlantic Ocean, where they spawn and die.

First things first: eels are fish.

How do fish swim? Having fins and tails help, But it takes more than that to be fast and avoid danger. Diving into fish physics.

From microbial biochemistry to recycling dead fish to manure-to-energy converters, here’s this week’s most surprising sustainability news.

From the "weird science" files: A research vessel off the coast of New South Wales in Eastern Australia hauled up a fish that did not seem to have a face.

Fish schools turn, contract, expand, even part and come back together all without missing a beat. Yet fish are individuals, not a hive mind.

Until recently, Americans did not generally consider fish to be wildlife. As a result, conservation measures for them got a late start.