News / Species Spotlight / Species Spotlight - Dream Fish: Blue Spotted Jawfish (12/06/17)

Species Spotlight - Dream Fish: Blue Spotted Jawfish

Species Spotlight - Dream Fish: Blue Spotted Jawfish

The Seasoned Aquarists Launch Pad to Difficult, Demanding, or Tank Busting Fish

Bright blue spots, yellow fins, a frowny face, and comical mannerisms these features are what draws me to Opistognathus rosenblatti, the Blue Spotted Jawfish. Blue Spotted Jawfish live in burrows on sandy rubble flats in colonies of up to several hundred fish in the wild. Their feeding habits, temperament, size, and great collection practices throughout their range make it a great candidate for home aquariums. Yet many aquarists still have issues keeping these fish! In this Dream Fish segment, we will explore basic husbandry of Blue Spotted Jawfish and the pitfalls aquarists face in their care.

Some quick stats about Blue Spotted Jawfish:

Max Size: 4
Min. Tank Size: 30 gallon
Aggression level: passive except to other jawfish
Reef Safe: Yes except for the smallest of shrimp species and sand dwelling corals
Range: lower three-quarters of the Sea of Cortez and the tip of Baja

When acquiring a Blue Spotted Jawfish look for one with a nice rounded body and avoid a fish that has a concave belly. A healthy Opistognathus rosenblatti has no coloration loss on its body. Avoid fish with red lesions, whitish patches, or roughed up scales, as this is often indicative of a common bacterial infection that newly imported jawfish can get. As usual, always buy a specimen that is already feeding at the store.

Blue Spotted Jawfish are not all that needy as far as diet is concerned. They dont need to be fed many times per day nor need a special diet. Any meaty food such as mysis, pacifica krill, brine shrimp, or flake and pellet is acceptable fare, which should be fed a couple times per day. A jawfishs belly should be rounded and slightly convex.

One of the largest aspects of jawfish care in general is their propensity to jump! A tight fitting lid is necessary to keep these fish in the tank! Any small hole in a lid is likely going to produce a crunchy jawfish on the floor. Overflows must also be covered or a ride to the sump will ensue.

Another crucial aspect is their need for passive tank mates. Even mild bullying can end tragically as infection from roughed up scales can become a bigger issue fairly easy for these fish. If severely bullied jawfish can stay hidden inside their burrows where, unfortunately, they can end up starving to death. Some sneaky aggressors that many aquarists may not think of being aggressive would include large species of blenny, hawkfish, and dottybacks.

As you can probably tell, a burrow is important to these fish as far as feeling secure in their environment. In the aquarium a three or four inch sand bed with various sizes of larger pieces of gravel to help stabilize their burrow is key to jawfish care. A small PVC pipe in the sand with an entrance just above the substrate can also work as an artificial burrow. Blue Spotted Jawfish will usually close off their burrow to intruders with a piece of rock at night to feel completely secure.

Finally, there are some aquarists that will swear that Blue Spotted Jawfish are cool water fish. That they do not live in reef temperatures, and face a quick demise if subjected to temperatures in the 70F. This misinformation stems from their range in the wild and the bacterial infections that come with importation at times. The Sea of Cortez is actually a subtropical body of water that varies quite a bit in water temperature- from the upper 50s in winter to the 80s in summer. This high variability of temperature makes Blue Spotted Jawfish comfortable at reef temperatures, but I would not exceed 80 degrees Fahrenheit for any length of time as a precaution. Breeding behavior has been observed in tanks in the 70s, another indicator that these fish are comfortable at these temperatures.

As always, quarantine is important in keeping these fish healthy by preventing obvious infective pathogens. They seem to be especially susceptible to eye flukes and bacterial infections. They are not sensitive to copper or praziquantel treatments if conditioned and feeding.

Wrapping up, Blue Spotted Jawfish can be excellent additions to your reef aquarium with a small amount of planning. They are hardy, passive additions that often bring some comedy to the aquarium!