Meet Washington State's only freshwater endemic fish: the Olympic Mudminnow! Despite being found nowhere else in the world, many questions about this quintessential Washingtonian species remain unanswered! On this episode, you'll get to know the habits, preferences, and close relatives of this beautiful little ambush predator. Ecologist Lauren Kuehne is our guest.

How well do you REALLY know one of the most popular fish the USA? What's the science behind its neon blue stripe? Where does it come from? What conditions does it prefer? Katrina and Guy get curious about this freshwater aquarium fish that Americans love so much.

Meet the Butterfly Kingfish AKA Butterfly Mackerel: the hottest fish you've never heard of! This not-well-studied fish is the sole species in the monotypic genus Gasterochisma, and the oldest lineage of Scombridae (the mackerel, tuna, and bonito family). Katrina, Guy, and guest Fernando Melendez Vazquez from the American Museum of Natural History in New York City dig into the details about this large, endothermic oddball and the broader topic of warm-bloodedness in fishes.

Get to know the Redbreast Sunfish and catch up on some fan mail, where Katrina and Guy read listener's fish requests and feedback! Learn how to tell this fish apart from other sunfish species, where to find Redbreasts, and gain some excellent fishing tips.

Get to know the minnow that "has the most normal looking head of any minnow" - the Weed Shiner! There's a lot of mystery surrounding this overlooked native fish, which, in addition to being a tasty treat for sportfish like Largemouth Bass and Bluegill, can tell us a lot about the success of habitat restoration efforts. Guest Ben Patschull from the Wisconsin Department of Natural Resources (DNR) tells an inspiring comeback story about this fish in "Pool 8" of the Upper Mississippi River.

Get to know the Gizzard Shad, a native fish that eats mud, feeds sportfish, and has something in common with birds! On this episode we delve into the ecology of this fish (including competition with invasive carp and positive interactions with native mussels), its nuanced role in nutrient cycling, and how the public perceives and interacts with Gizzard Shad. We've even got some math for folks who like working with numbers and want to optimize decision-making in fisheries. Our guests are Mike Vanni from Miami University and Richie Erickson from the USGS Upper Midwest Environmental Science Center.

Get to know the only surviving member of genus Empetrichthys, the desert-dwelling Pahrump Poolfish! This Nevada native is not nearly as well-known as its neighbor, the Devils Hole Pupfish, but similarly is endangered and endemic to isolated, highly specific desert habitat. In six seasons of Fish of the Week, this is the FIRST species we've covered in the family Goodeidae! Our guests are fish biologists Kevin Guadalupe from the Nevada Department of Wildlife's Native Fish and Amphibian Program and James Harter from our Southern Nevada Fish and Wildlife Office. You'll get a slice of history, hear about a creative and collaborative conservation approach, and leave with hope for the future.

You might also enjoy these episodes:

• S1:E46 - Devils Hole Pupfish: A Tiny Oasis
• S2:E14 - Rio Grande Suckers
• S2:E30 - Long Valley Speckled Dace: Cryptic Desert Fish
• S4:E39 - Owens Pupfish: Blue California Jewel
• S5:E19 - Rio Grande Silvery Minnow

Get to know the habits of the Blacktip Shark and why they aggregate so close to shore. Just in time for summer, Katrina and Guy visit with shark expert Stephen Kajiura from Florida Atlantic University about shifting baselines and why these sharks are adjusting their migration farther north up the East Coast. We discuss how scientists study these sharks, what drives their migration, beachgoing safety tips, fishing considerations, and what it's like to be a shark biologist.

If you like sharks, you might enjoy these episodes as well:

• S1:E29 - Salmon Sharks
• S2:E42 - Goblin Sharks
• S3:E29 - Greenland Sharks
• S4:E23 - Pacific Sleeper Sharks
• S4:E30 - Blacktip Reef Sharks
• S4:E49 - Cookiecutter Sharks

The scene is set: two neighbors with very different ways of living. One is large, long-lived, free-to-roam, blimp-like. The other: small, shorter-lived, confined, butter-like. These are the people's fish, occupying international waters and places on earth that are quite impossible for us to truly experience from the perspectives of these amazingly adapted, beautiful fish. Get to know the "albatross" of the abyssal plain, the unfortunately (or fortunately?) named Robust Assfish, AND the Atacama Trench Snailfishes in our first ever compare and contrast episode.

Our guest, Dr. Thom Linley, is Curator of Fishes at the Museum of New Zealand Te Papa Tongarewa and co-host of The Deep-Sea Podcast.

Other episodes you might like:

• S3:E25 - Mariana Snailfish: Trench Fish Extraordinaire
• S4:E13 - The Unassuming Bony-eared Assfish!

Read more:

Fishes of the hadal zone including new species, in situ observations and depth records of Liparidae: https://www.sciencedirect.com/science/article/pii/S0967063716300656

Independent radiation of snailfishes into the hadal zone confirmed by Paraliparis selti sp. nov. (Perciformes: Liparidae) from the Atacama Trench, SE Pacific: https://link.springer.com/content/pdf/10.1007/s12526-022-01294-0.pdf

Get to know the Gilt Darter complex! Katrina and Guy are joined by two guests from Yale University's Department of Ecology and Evolutionary Biology: Tom Near and Julia Wood. They imagine sitting down with the five species (Gilt, Masquerade, Brassy, Western Gilt, and Russet Darters) over dinner to understand the identity of each fish and how they're doing, dig into what makes a species a species, the definition of a species complex, and how the advancement of biodiversity discovery is important to conservation.