Jawfish make excellent fish for nano reef aquariums

Features, Fish | 17th March 2013 | Article by Albert Thiel | View comments (4)

Jawfishes that are most commonly found in the aquarium trade are of the Genus Opisthognathidae. There are however other genuses, for example: Lonchopisthus Jawfish, Merogymnoides Jawfish, and quite a few more.

Yellow Faced Jawfish - Opistognathus aurifrons

Yellow Faced Jawfish – Opistognathus aurifrons

The latter genuses are however not often encountered when one visits fish stores, or even online sellers. The main reasons appear to be that either they are not often collected, or that there is little demand for the species in those genuses, and with little or no demand there is no incentive for divers and commercial fish collectors to bring them to market.

That does not mean, however, that some of the species in those genuses are not desirable, on the contrary, some are quite stunning. Jawfish, in fact, make excellent additions to nano reef tanks, the type of reef that is nowadays kept by more and more hobbyists, perhaps because of the lower expenses associated with keeping such aquariums, but also because their overall maintenance and husbandry is far more manageable than what it would be for the larger type reef aquariums that were the norm just a few years ago, and still are of course but to a lesser degree.

It also seems that many newcomers to the hobby opt to start reef keeping on as smaller scale setting up aquariums in the 10 to 30 gallon range, which is generally considered to be a nano reef, even at the high end of that range.

Jawfish are often similar to Blennies, but are generally smaller in overall size although, in general, they exhibit a longer body than most Blennies do.

Jawfish heads, mouths and eyes are fairly large for the most part, compared to the rest of their body. Jawfish have a single, long dorsal fin with anywhere from 9 to 12 spines. Jawfish tails can be rounded or pointed, depending the genus and the species.

Species in the genus Opisthognathidae discussed in this article will, at times, show a slightly different coloration depending on their geographical origin. The Yellow Head Wrasse O. aurifrons is but one example of that exhibits that trait.

Most, if not all Jawfish, live in burrows that they build in sandy substrates. They fill their mouths with sand and spit the sand out in another spot, eventually creating a tunnel inside their burrow. This is unlike what many burrowing Gobies do, as they create short ones with no tunneling that extends several more inches underneath the sand. Jawfish burrows can therefore become quite intricate. Of course we hardly ever have a chance to see the full extent of them, but such is what those who study their behavior have found.

Utilizing their burrow to dash out of, they feed on plankton and other small life forms that float around in the water column, ready to dash back into their “safe” place at the first sign of danger. They are definitely also very protective of the area around their burrows. The size of the area they protect depends on the species but is, in most cases not very large, usually about a foot or slightly more the location of that burrow.

Blue Spot Jawfish - Opistognathus rosenblatti

Blue Spot Jawfish – Opistognathus rosenblatti

Jawfish Mouth Brooding

Jawfish Mouth Brooding

Jawfishes are mouth brooders, keeping eggs in their mouth where they will hatch and be protected from other fish that may try to predate on the young.

Typically it will be the male who carries out this function and it may last anywhere from 7 to 12 days, sometimes a little longer for certain species, at which time the fry will be released but will remain very close to the female, thus gaining protection and safety for another varying number of days.

Hobbyists have kept different types of Jawfishes successfully for some time now, but only if their aquarium, or Nano-Reef, has the right type of substrate, and when that substrate is deep enough for the Jawfish to dig its burrow and tunnel (meaning that the burrow extends further backwards into the substrate).

The recommended type of substrate is a mix of 2 parts fine and 1 part coarse sand or crushed coral. Mix both types real well, and create an area in your Nano-Reef where your substrate is at least 3 to 3.5 inches deep.

Hobbyists do not need to have that depth in the entire aquarium though; however the minimum recommended overall size of the deep substrate area should be at least 7 by 6 inches.

In order for Hobbyists to be able to see the burrow and the Jawfish, situate that area in the front the tank, for instance in either the right or left corner. When adding the Jawfish to your Nano-Reef, release it in that area of the tank, using a small plastic container to hold the fish in, preferably not a net.

Make sure that your Jawfish has been properly acclimated and for a sufficient amount of time. Floating the bag in which it came Is not recommended. Use a separate container, and drip acclimate the fish for 30 or more minutes, longer if the parameters of the water it came in show a large difference. Remember that some Pet stores will keep fish in low salinity tanks to reduce the possibility of diseases.

Most Jawfish of the Opistognathus genus are relatively small and can be kept with non-aggressive fish in a Nano-Reef of at least 20 gallons, but preferably more (a 40 gallon Breeder tank would be an ideal one to stock a pair of mated Jawfish).

I stated that most are small but there are some of this genus that get quite large, for instance Opistognathus rhomaleus can easily get 20” long. Of course you will not find the larger ones offered for sale in the hobby, and many Stores and Resellers do not even offer the smaller ones for sale, but with a little research you will be able to locate whichever one you have decided to acquire for your aquarium.

Jawfish are a lot of fun to watch and are easy to care for as long as you do not house any bullies in your Nano-Reef, as in such cases they will remain in their burrow and you will not see them all that much. Without bullies though Jawfish will spend time in and out of their burrows and exhibit interesting behaviors. Some even call them “people watchers” meaning when you are close to the aquarium (after a while) the fish will come out of its burrow, possibly a reaction to getting ready to feed.

They need meaty foods, small ones, such as newly hatched brine, small Mysis, California Bloodworms (Lumbriculus variegatus) and the like. They will also feed on rotifers and copepods if any are present in the Nano-Reef. If you are going to feed worms make sure they are the California ones and never feed too many at once as they only survive for about 15 seconds or so in saltwater. They are very nutritious and are considered “complete” foods.

With proper care and high water quality your Jawfish will do very well and will be the pride of your Nano-Reef for sure. If at first you have problems feeding them, try the spot feeding method and make sure other fish are not swimming over to the Jawfish area to “steal” the food. Also, make sure that you have a guarantee from the seller that they are feeding, and know what they are being fed by them so you can start them off on the same foods.

Blue Spotted Jawfish in BioCube 29G Reef Aquarium

More information on the Jawfishes can be found in my new Book: “Nano-Reef Aquariums” that should be available later in March 2013.

About the author:

Albert has published a number of reefkeeping related books including possibly the first book on 'nano reefing' entitled, Small Reef Aquarium Basics - for smaller tanks and for beginner hobbyists. Other titles include the best selling The Marine Fish and Invert Reef Aquarium, Advanced Reefkeeping I, Advanced Reefkeeping II (e-book) and The New Marine Fish and Invert Reef Aquarium (e-book). In addition to his books, his work was regularly published in magazines including his own monthly, The Marine Reef Newsletter. In addition to his writing Albert has spoken at numerous aquarium conferences and meetings across the world. Albert is currently finishing up his latest book, Nano Reef Aquarium. Click here to pre-order your copy of this exciting new book.

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4 Responses on Jawfish make excellent fish for nano reef aquariums

  1. […] Nano-Reef Aquariums is longer than this article and includes all the necessary copyright mentions Jawfish make excellent fish for nano reef aquariums | NanoReefBlog Note that you can still order my Book at the reduced pre-publication price and get a 1 year free […]

  2. […] the Nano – Reef (an excerpt from my new book but not the full text of what is in the book itself) Jawfish make excellent fish for nano reef aquariums | NanoReefBlog Albert Ask Nano Questions and Find Information (Nano Expert Albert Thiel) ……. … […]

  3. Nick Hatton says:

    I really like the look of the blue dot jawfish but it was £140 in my lfs.

  4. Albert Thiel says:

    Yes O rosenblatti can be quite expensive indeed but 140 pounds seems like a lot … how large was it ? Fully grown? Here on eBay for instance $90 is about what they are sold for.

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