I know this a little bit of an old thread but I thought I'd throw in my experience anyways; I have a 28 gallon nano cube, no refugium, with about 28lbs live rock and 15lbs of sand... All of this has resulted in a very plump, happy, and healthy mandarin dragonet... By now most of you are probably going, "What!?!?" ...am I right?
I setup my nano cube, got it cycled, and ready for fish and corals, etc. After the tank had been running for about a month and a half, maybe two months, I had a few small Zoa colonies, and I decided it was time for a fish. I was originally going to get the mandarin as the last fish, but somehow it ended up going in first. He was a little thin when I got him, and didn't eat any prepared foods at the time. I tried to get him to eat some prepared foods over the next couple weeks, but he never really took to the idea. I did add a bottle of live copepods when I first got him, so I knew he wasn't starving, especially since he fatten up pretty quickly, and has stayed nice a plump since then. I decided I would setup a small fuge in an Aquaclear power filter, but that sort of didn't work out, and actually caused more problems than it solved (mostly my fault because of how I set it up...). Anyways, after about a month of running the fuge, this was about 4 months after I started the tank (~2 months after getting the mandarin), I took down the fuge, and just added more copepods, as well as some rotifers. Since then I haven't added anything else, as far as pods or other food for my mandarin, and he has stayed very active and healthy/plump. I have decided to use the sump of my nano cube as a refugium, with some live rock rubble, chaeto, caulerpa, and some mangroves. This will be fully completed within the next week or so, and I have also bought some more rotifers and copepods that have been added to the tank, and into the refugium. My reason for setting up the refugium is actually not at all for the mandarin (who is nice and plump on his own
), but for helping with my water quality. I don't have high nitrates, nor any phosphates, but I have been getting bad hair algae and Cyanobacteria since I setup the tank. I have also ordered a very strong cleanup crew, so that should take care of these problems. Anyways, I think it will be fun to see what happens with my tank once I have the refugium running.
I have no doubt that the difficulty that is often associated with these fish is, of course, because of their diet. I feel that as long as the tank has had enough time for a healthy pod population, not necessarily large, to exist, you can keep these fish without to much trouble, at least not feeding trouble. As long as you supplement a large amount of copepods and other micro-organisms, provide plenty of places for them to live and reproduce (algae, plants, rocks, sand, etc.), and don't kill them with a UV sterilizer, then you pr tank should be able to support a mandarin. Granted some tanks, just are too small for a mandarin (probably anything below about 20-25 gallons) without frequent supplementing/replenishing of the pod populations. If your tank is large enough to support a mandarin, but you, like me, don't want to go way out of your way or original plans for the tank, in order to keep one, just be sure that you add some copepods and other small animals (rotifers, amphipods, isopods, etc.) to your tank, provide some places for them to live (there isn't a need to buy a mass amount of macro algae for a refugium, or have huge refugium to begin with...just make sure that there are some nice clumps of algae or plants in your tank - hair algae is even suitable, though obviously it doesn't look very nice- you also will need to make sure that there is an adequate amount of good quality live rock, which should be about 1-2lbs per gallon. I think that mandarins are often thought of as much more difficult than they actually are... However, they are not for a beginner aquarist unless you have the proper setup, knowledge, and are willing to purchase copepods on a regular basis, incase your mandarin isn't getting enough food from your tank.
I hope all of this was helpful to somebody, and I do realize that there are people who will think I am crazy for making mandarins sound "easy" in some ways, but I really do think that they are easier to keep than they are often thought of, though as I have said, they can be challenging fish depending on their tank and environment.