Meet the Expert Studying Fishes That Spit Water to Hunt

Smithsonian Ichthyologist Matt Girard talks about how and why he studies archerfishes.

Red xray of a fish on black background.jpg
There’s a group of fishes that shoot water from their mouth to stun prey. Matt Girard, an ichthyologist at the Smithsonian’s National Museum of Natural History, studies these fishes to learn more about what makes them genetically and structurally unique. Matt Girard, Smithsonian

In Australia and Southeast Asia, some fishes hunt a little differently. These animals, called archerfishes, use an unorthodox method. They shoot water with their mouths to stun prey for an easy meal.  

Archerfishes are an enigmatic fish family with an obscure evolutionary history and family tree. That’s now beginning to change, in part due to scientists like Matt Girard, ichthyologist and postdoctoral fellow  at the Smithsonian’s National Museum of Natural History.

For this “Meet a SI-entist,” Girard, who recently won an award from the American Society of Ichthyologists and Herpetologists for his upcoming paper on archerfish evolution, talks about how and why he studies these strange “spitting” fishes.

Girard studies archerfishes, examining specimens like the one shown in hand and on the computer screen, to understand how they hunt the way they do. Matt Girard, Smithsonian

What caused you to study fishes and become an ichthyologist?

It's a funny story. When I was a kid, I didn’t know ichthyology was a career. I grew up watching tropical fishes and moved between Hong Kong and Florida. I always loved fishes and thought they were neat. But, at most, I thought I'd have an aquarium when I grew up. 

Midway through college, I went on a trip for an ecology class, where we collected some fishes in Northeast Illinois. After the trip, I sat in the laboratory for a week nonstop identifying our specimens. Doing this identification was so cool to me. It crystallized what I liked about fishes — studying different groups by examining their anatomy. 

Now, your research focuses on the fish family called archerfishes, which are known for their ability to shoot water, or “spit,” to stun prey. What led you to them?

I was working on a project asking questions about how different fish families, including the archerfishes, were all connected evolutionarily. After learning more about this family, I basically went archerfish crazy. They're fun and charismatic. 

A lot of people are familiar with the fish that “spits,” but my interest in these fishes actually started for another reason. I was initially interested in what makes an archerfish an archerfish in terms of its evolution and characteristics. 

Archerfishes, like the species Toxotes blythii, are famed for their ability to shoot water and stun prey. They’re also known for their frilly fins and colorfully-patterned skin. Matt Girard, Smithsonian

To answer this question and others, my research spans not only anatomy but also genetics through DNA sequencing. I use both of these techniques to look at how evolution has occurred in archerfishes and the results of this work will be published in a new paper that comes out soon.

Studying these fishes, their anatomy and their genetics can tell us a lot about how they evolved. It's important to learn about their evolution because they’re such a unique family. No other fish hunt this way. I want to know where archerfishes belong in the tree of life and what families are their closest relatives so we can understand how their neat behavior evolved.
Do you have a favorite species of archerfish?
The archerfish I like the most is the one that so few people know about. It's called the primitive archerfish and doesn’t have stripes or spots. It’s my favorite because of the genetic and physical differences between it and other family members. 

Actually, some of the physical characteristics that make primitive archerfish different lie in their mouth structures. Mouth shape affects how archerfishes shoot water. So, looking at differences in their mouths can reveal clues about the family’s evolution.

Unlike its family members, the primitive archerfish, Toxotes lorentzi, has no stripes or spots. Matt Girard, Smithsonian

You're also a skilled photographer. Tell me about how this passion intersects with your ichthyology research.
A picture is truly worth a thousand words. It’s one thing to sit there and say this fish or fish bone is bigger or smaller, but when I take a photo, that’s when you can see what I mean.

In a way, I've become a more descriptive researcher because of my photography. It’s taught me that it’s one thing to look at something in a microscope and another thing to put it on a page in the way that people can clearly understand what is interesting. Because of those lessons, I take photographs for my papers, some of which you can see here.

Besides providing specimens to photograph, how does the museum’s National Fish Collection intersect with your work? 
Well, people have been collecting fishes for hundreds of years, but archerfishes are a particularly tricky group to find in collections. A lot of collections have a handful of specimens, but many people don’t even know that there’s more than one or two species. 

For example, the primitive archerfish is a particularly rare specimen to have. But the Smithsonian has a jar with nine primitive archerfish specimens. To my knowledge, it’s the only jar of them in the United States. 

So, the museum is critical for my work, because if I'm going to ask questions about how primitive archerfish and their family members have evolved, I need to study as many of them as I can. 

This interview has been edited for length and clarity.

Meet a SI-entist: The Smithsonian is so much more than its world-renowned exhibits and artifacts. It is a hub of scientific exploration for hundreds of researchers from around the world. Once a month, we’ll introduce you to a Smithsonian Institution scientist (or SI-entist) and the fascinating work they do behind the scenes at the National Museum of Natural History.

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