Deer arcprolife:
I absolutely love the psychedelic coloration and peaceful nature of Mandarin dragonets! There’s no disputing that they are gorgeous little fishes and make ideal tankmates for seahorses in the right type of setup. They are docile, slow-moving, passive fish that are beautifully marked and very deliberate feeders. And they are quite hardy fish providing they can be fed properly. They have a heavy slime coat that seems to make them quite resistant to protozoan parasites such as Cryptocaryon irritans.
But in order to do well, mandarins need a large, well-established aquarium loaded with live rock that’s teeming with copepods and amphipods. As you know, mandarins must have continuous opportunities to graze on suitable live foods or they generally slowly waste away and starve to death. In the right system, they can thrive, and will often learn to take small pieces of frozen Mysis, but they do best in well-established reef systems or aquariums with at least 1 pound of live rock per gallon, a mature sand bed, and a refugium that can continually replenish the pod population in the tank. Those are typically the conditions that are necessary to assure they have adequate suitable live prey.
It’s going to be difficult to provide them with the conditions they need to thrive without live rock in the aquarium. The live rock provides the shelter and feeding opportunities that the copepods and amphipods need in order to build up and maintain a breeding population. Without the live rock, and with several hungry seahorses competing with them for the available pods, it will be challenging for you to provide a Mandarin goby with enough to eat. Your 57-gallon tank is borderline large enough to support a Mandarin, but if you want to give it a try, I wouldn’t introduce a Dragonet until the tank was at least one year old.
And I would only consider a Mandarin if you can equip the aquarium with a good refugium as well. As an example of the type of refuge that produces good results for mandarins and seahorses, Charles Delbeek likes to use colonies of glass shrimp and cleaner shrimp that in the refugium for his seahorse tank, where the regular reproduction of these hermaphroditic crustaceans will provide a continuous supply of nutritious nauplii for his ponies:
"There is a method that can be used to offer an occasional supply of live food for your sea horses. By setting up a separate system housing several species of shrimp such as the common cleaner shrimp (Lysmata amboinensis) or peppermint shrimp (lyse model wurdemanni), or Rhynchocinetes uritai or R. durbanensis, you can get a fairly regular supply of live shrimp larvae. These species are best to use since they can live in large groups and spawn on a regular basis. Such a system is commonly called a refugium. A refugium is a small (10-20 gallon) aquarium that contains live sand, live rock and/or macroalgae such as Caulerpa. It is plumbed such that water from your main system is pumped to the refugium and then returns via an overflow to the main tank. For this type of arrangement to work, the refugium must be slightly higher than the main tank. Shrimp are added to the refugium and within a few months they should start spawning and hatching eggs every few weeks. The larvae are then carried back to the main tank by the overflow, where they become a food source for your sea horses. Of course other life will also thrive in the refugium and it is not unusual for copepods, mysis and crab larvae to also be produced on a regular basis. The key to the refugium is to keep predators out of the system so that the smaller micro-crustacean population can thrive. You would need a fairly large and productive refugium to produce enough food to maintain even a pair of sea horses, so at best, a typical refugium can provide a nice source of supplemental live food; the basic daily diet still needs to be provided by you in the form of the frozen foods mentioned above." (Delbeek, November 2001, "Horse Forum," FAMA magazine)
Aside from the one Delbeek favors, refugia are available in a number of different designs. For example, there are easy-to-install external hang-on refugia and in-tank refugia as well as sump-style refugia that are mounted beneath the main. In the case of the latter, the refugium is installed exactly like any other sump. Here are a couple of online sites where you can look up more information on refugia, including articles explaining how to set up and install a refugium of your own:
Click here: Refugium Setups Information – From About Saltwater Aquariums
http://saltaquarium.about.com/od/refugiumsetups/
Click here: Refugiums
http://www.wetwebmedia.com/refugium.htm
A good refugium is all the more important in the aquarium like yours that lacks live rock. So if you want to add a Mandarin to your system at some point, I would establish a refuge as described above and then wait at least a year for the sand bed and refugium to mature and build up a large population of copepods, amphipods, and steady supply of larval shrimp before you actually introduce the Dragonet.
Best of luck with your new seahorse setup!
Happy Trails!
Pete Giwojna
Ocean Rider, Inc. is an Organic Hawaiian-Based Seahorse Aqua-Farm & Aquarium that Follows Strict Good Farming Practices in Raising Seahorses and Other Aquatic Life.
