Fish

Soft tissues don’t fossilize well, so scientists have to infer organ anatomy from bones. But an unexpected treasure trove of new information has been discovered in Australia, with a 380-million-year-old fish fossil preserving the oldest heart ever found.

We already know that waterborne plastic particles can enter the bodies of fish, which are then eaten by humans. New research, however, shows that such particles can enter the food chain via another route, by traveling from plants to insects to fish.

Even though the basking shark is the world's second-largest fish, much of its life has eluded observation. Now, however, researchers have determined that the usually solitary animals find mates by meeting up and circling around one another.

After being introduced to Russia's White Sea, non-native Pacific salmon have since spread along Norway's coastline and into its rivers. In an effort to control their numbers, an AI-enabled fish-identifying gate has been placed on a Norwegian river.

While the farming of salmon does help take pressure off wild stocks, the feed used to raise the fish still isn't entirely sustainably sourced. That may change, however, thanks to nutrient-rich worms that eat readily available seaweed.

Despite protective measures, endangered fish species are regularly caught then sold in open markets. And while visually searching them out can be difficult, a new technology could more easily allow authorities to know which species are being sold.

While many people love the taste of smoked salmon, not everyone is comfortable with wild fish being netted, nor with captive fish being farmed. Such folks may be in luck, as a new smoked salmon substitute is in the works – and it's made of algae.

One of the ironies of salmon farming lies in the fact that although the salmon themselves aren't wild-caught, their feed is made up of fish that are. According to new research, it would be ecologically better if we just ate those feed fish ourselves.

Researchers at Harvard and Emory have created a biohybrid fish out of human heart cells that swims autonomously for months at a time as the cells beat. The project is a sidestep on the way to eventually growing new functional hearts for transplant.

We generally don't think of fish as being a vocal bunch – after all, anglers don't typically use "fish calls" to lure them in. According to a new study, however, approximately two-thirds of all fish species probably use sound to communicate.

German scientists have announced the discovery of what is claimed to be the world's largest fish breeding area known to date. Described as a globally unique ecosystem, it consists of tens of millions of icefish nests on the Antarctic sea floor.

Scientists have managed to watch memories form inside the brains of live fish in real time. And the results were intriguing – synapses formed in one part of the brain while disappearing from another, rather than strengthening as previously thought.