The Joy of Jawfish

In Spanish, this fish is called Traganavis Dorado. Which we love because it translates roughly as the golden swallower. From this, maybe you can guess what the most common English name for this fish is already, yup, Yellowhead Jawfish; sometimes also called Pearly Jawfish. Scientifically this fish goes by the name Opistognathus aurifrons. Another interesting moniker for this fish comes from the ABC (Aruba, Bonaire, Curacao) Islands, where it is called the Jack in The Box. This comes from their activity. Understand that it is a burrowing fish, and they both dart into their burrow to avoid danger and pop out of it to look around when they think the danger has passed. This activity, popping their heads out of the sand, earned them the Jack in The Box nickname.

As a result of their burrowing nature, they obviously need substrate. In the wild, they find this near rubble and coral reef edges, and usually in fairly shallow water; think less than 40 feet down, but it could be as much as 100. In the home aquarium, they won't need the depth, the rock, or the coral, but they're still going to need some sand and the right sand is an important part of the husbandry of these fish. You want something with mixed grain sizes, and even some coral rubble mixed in wouldn't hurt as it will help support the burrow they dig. The internet is full of sources saying you need four full inches of sand for them, but two to three where some spots are deeper than others is plenty. You can use live rock, cultured rock or faux rock in a tank for Yelllowheads, but it isn't strictly necessary (it's still good for filtration and looks nice). If you do decide to aquascape with rock, make sure it is sitting firmly on the bottom of the tank, and preferably affixed there so that it can't be undermined by your digging obsessed fish!

Yellowhead Jawfish don't need a lot of space, and you could keep one in a tank as small as 30 gallons. They average around three to three and a half inches long, and even in the wild, don't stray too far from their cave. They're also often found in groups, and you can emulate this in a home display as long as each individual fish as everyone has room to dig their own burrow; each fish should have between a square foot and two, so in a 75-gallon tank, you could have three or four! Any display with Jawfish should be covered, they are all surprisingly adept jumpers. Flow should be moderate as your Yellowheads will like to suspend themselves in the current and feed on whatever floats past.

That wild feeding behavior makes for a fish that isn't all that picky when eating in the home aquarium. They'll take generally any frozen / thawed food that floats past them, and it's the “floating past them” that's the tricky bit. They'll learn in time to be bolder at mealtime, but initially it's fairly likely that you'll need to make sure food floats past their hidey-hole more than once a day. We use Gamma and Nutramar Foods here almost universally and suggest you do too. The Yellowhead Jawfish will love the Mysis, Chopped Prawn, Rotifers, Copepods, Chopped Mussel, and all the Brine Plus products Gamma offers. We suggest offering them some Nutramar Complete Pellets mixed in with the meaty offerings so they start to associate those with food as well, which usually doesn't take more than a few feedings. As we offer both here, your fish may come already looking for bits of processed food!

Yellowhead Jawfish are very peaceful fish, and this should be your goal when looking for other fish to keep them with. As we've touched on, they're good with other Yellowheads, but might either bully, or be bullied by Jawfish of other species. If you were going for the peaceful Caribbean style aquarium, you could keep a couple with some Neon Gobies, and a Candy Basslet (and maybe some Blue Chromis). What you want to avoid is large, bold, aggressive fish, like Queen Triggers and French Angels. Even Caribbean Blue Tangs are probably going to be too much activity for the Yellowheads to stay out in the open. This limited array of choices most often means mixing Yellowhead Jawfish with species from other oceans (which is the norm for almost all aquariums we see). Think about utilizing fish like all the various Cardinals which make perfect tankmates for Jawfish. Filefish, Canthigaster Puffers, peaceful clowns like Ocellaris, and all the various Dragonettes as well as slower, peaceful wrasses like Macropharyngodon are all the right kind of temperament for mixing into this kind of display and could all make for a really beautiful tank. Just a word of caution when mixing fish from different oceans; quarantine is always an important aspect of fish husbandry, and it is even more important when adding fish from distinct origins that have slightly different pathogens in their home waters, and thus, slightly different immune responses.

While Yellowhead Jawfish bear a passing resemblance to Yellowhead Sleeper Gobies, both are very distinct critters, and the Jawfish is a less complicated fish to maintain long term, being both easier to feed, and generally hardier. Yellowhead Jawfish aren't that picky about water chemistry, being fine in a range of parameters as long as they are stable. Specific gravity can be anywhere from 1.020 to 1.026, pH between 8.1 and 8.4 and a temp anywhere between 70 and 78 Fahrenheit. In regard to water quality, nitrates should be as low as possible, ideally staying under 1ppm.

Opistognathus aurifrons from different parts of the Caribbean will have slightly different patterns, but as of the writing of this article, these differences haven't been linked to genetic variation, so they are all (for now) one species. Yellowhead Jawfish are incredibly active, colorful and interesting, and they are definitely something a little bit different for the marine aquarium. They're low risk with most invertebrates and generally considered reef safe except for occasionally burying a coral on accident. Looking for something just like this for the lowest reaches of your peaceful aquarium display? Today is the day, ask your LFS about getting you a couple few Yellowhead Jawfish from Quality Marine!