20long Dragonet Tank

[MiltonP]

Didn't consider the eggcrate for a divider. I suppose I only need a sandbed to surface zone that the dragonet can't reach. There won't be any other predators to worry about and eggcrate would allow plenty of flow so I shouldn't need a powerhead in the 'no fish' zone.

The question is will I be able to keep a large quantity of macro-algae contained in the zone or possibly keep an algae feeder (snails?) contained in the fish zone.

 

[CAT]

I wouldn't keep the macro algae contained anywhere in the tank -it's a good place for the pods to hide while the mandarin is hunting -more natural.

 

[rlp1]

You asked for comments on using a 29 gal instead. I vote for the 29. It is approx 5"(?) higher with the same footfprint as 20L. This would give you more room for a deeper sandbed while still having 12" or so water column to pack rock in. After you put your sandbed in a 20L you're not going to have very much height left to pack rock in.

Also, couldn't a mandarin swim right thru eggcrate? The last eggcrate I bought had openings that measured 5/8". The older eggcrate I had measured 1/2" openings so they seem to be making it flimsier now. One time when I had my mandarin in a tank with a divider, I staytied plastic window screen to it because I was afraid he might swin thru it.

My mandarin also eats live black worms. Also, as someone else said, I have witnessed my mandarin eating small bristleworms.

My last idea would be to put the divider in the middle of the tank & then alternate the mandarin to either side every week so that pod population can build back up on other side. Just lift up the divider & let him swim under it. Good Luck. Rita

 

[bowser]

My only concern with using the eggcrate as the divider is that the adult pods might all migrate out of the refuge.....not really sure though.....????? Anyone with experience on this?

Cat has a point about the holes plugging up, yet a quick scrub with a toothbrush kept only for your tank should clean it up just fine.

Let me explain my refugium....it's small, almost ridiculously small compared to the rest of the tank. About quart size. It hangs at the top of the tank in the back corner just a little bit under the water level so circulation is provided. (Right next to a powerhead with the direction aimed somewhat at the refugium). I read about this on another site and thought I would try it, this is a fish container meant to hold sick fish or perhaps freshwater livebearers. Solid plastic with the exception of the bottom which has slots. I then took another piece of plastic that has 8 tiny holes and covered the bottom. A few shells, a small piece of rock and filled it with feather and grape macros. The adult pods can only escape this by going over the edge which most seem reluctant to do. Their offspring can go through the little holes, and most of them do! Inside the refuge you can see many adult copepods, and amphipods, and some of their larvae, yet outside the refuge, you can see tons of the larvae crawling all over everything. They are so small that the other fish don't bother with them which gives them the opportunity to get into the rocks and sand. Once they start growing and they get a certain size the mandarin will then take them. Even though this is a good size tank, there is only about 45lbs of rock in there as this a FOWLR.

 

[bowser]

So many good ideas!!

I like the idea of switching sides too....if you did that once a month or so, then that would give the offspring on the opposite side time to mature and reproduce.......

 

[MiltonP]

I picked up eggcrate today. The openings were 9/16" which might allow a small dragonet through if used for the divider. I don't think one would try unless hunger was an issue. The plastic dividers I saw were too flimsy but I may order one that looks on the web.

I don't think I want to split the tank in the middle as that cuts down the area for the fish a too much. I am still leaning towards 25% for the refuge though maybe I could switch it from end to end. Bowser's internal hang-on might be worth a try first. If it does the job, I am sure the mandarin would appreciate the additional territory.

I made a platform for the rocks and will make 5" pvc pilings tomorrow. I layed it out so that I could hide a few of the pilings out front with rocks on the tank floor creating more of a natural cavern look. I hope to start curing rock within a few days.

 

[MiltonP]

I made the platform to suspend the live rock. The 12" tank height of the 20L was no good and I really want to have plenty of bed available for munching.

I am going to move my freshwater 29 inhabitants to the 20L. The 29 is 8 years old so I may switch to a 37 and gain even more height for internal refugium options.

 

[CAT]

What about a hang-on refugium? I know CPR makes one, there are probably other types as well.

 

[MiltonP]

I like the CPR external refugiums. The only problem I have with it is that it is out of site when on the rear and won't fit the side of the 20L or 29 aquarium. The only view will be straight down. I thought about positioning the tank perpendicular to a wall but it made for a strange floorplan.

The CPR internal uses suction cups and is too small. I briefly considered modifying a pair of them to hang-on.

 

[CAT]

So, sounds like you now buy the acrylic and make your own internal refugium Could be done with the 29, I think. Maybe the DIY forum has some suggestions...

Good luck

 

[Anonymous]

I'll lend you my 2 cents here as a successful mandarin keeper...
One of the most important factors is the age of the sand bed. A sand bed that is 4 or 5 months old will not suffice, especially in a tank so small. Same goes for a refugium.
I have a 2 year old sand bed in a 30 gallon that produces more pods than a single mandarin could possibly eat. The tank MUST BE WELL FED! This enables the pod population to keep up with the mandarin. I feed very heavily, to the point where I sometimes battle nuisance algea. It's not a major concern though - you learn the limits. It's a balancing act.
The mandarin is now in a 90 gallon corner, with a much younger sandbed. It was seeded with the older sand bed however, and I harvest pods out of the 30 gallon from time to time.
The 90 gallon also has pod piles all along the back, which are kicking in just fine now after 6 months or so and producing a fair number of pods.
My mandarin has gown a 3/4" in the last few months, and her belly is always round.
Lastly, the nature of the live rock is important, especially if pod piles or a refugium are not present. Some live rock is more porous than other live rock. You want the live rock with all kinds of nooks and crannys. Small holes and caves that the fish can't possibly get into. This makes a HUGE difference over using live rock that lacks this feature.
All these things in conjuction will usually do the trick, but not always in a tank as small as the one you're proposing. Every tank is different...
Hasta
Jim

 

[SPC]

Well said Jim, excellent advice!
Steve

 

[MiltonP]

Jim, Can you give me more info on the 30 setup, ie...filtration, skimming, etc... I would also like to know more about the feeding regiment you referrd to. Who else was in the 30 with the mandarin prior to the move? Thanks, Milt

PS - the 20L is now occupied and the 29 should be cleaned out tomorrow

 

[Anonymous]

It's a sumpless tank with a crappy Red Sea skimmer hanging on the back. (was skimmerless for a long time) The tank used to house a clown, a pigmy angel, and a sixline wrasse that were placed in that tank when I had a moving disaster with my 92 corner. The sand (couldn't fit all of it obviously), rock, etc were from that tank. After a while I set the 92 back up, and put the 3 fish back in the bigger tank. By this time though, that old sand bed was a few years old, and really thriving! So I put a small female mandarin in the 30, and she really took off! The pod population was reduced after a few weeks, but stabilized at what was still a very high density. I fed the tank daily with flake, shrimp, frozen food, whatever. Just for the pods. This encourages the growth of turf algea, wich also provided more homes for the pods. Now, the mandarin is in the bigger tank as well, and growing still. That 30, now that the mandarin is gone, has so many bugs in it I could probably sell kits out of it! I've never seen such a density of pods and various other bugs. It houses a sixline grouper, who eats a ton and produces a fair amount of waste, so the pods just breed like mad.
A little tip I forgot to mention before, the top layer of your sand bed should be rather course, like what would fit on top of this underscore _ maybe a quarter of an inch or so. This will provide breeding substrate for the pods, whereas just fine sand really doesn't provode them any cover.
This REALLY helps things.
I would encourage you to try maybe a 55 gallon at least for this project...
Cheers
Jim

 

[bowser]

When I first started saltwater, I did like many and used crushed coral as my substrate (I had no internet at that time), and one thing I did notice was tons of life in the cc.....pods, worms, small brittles, etc...
Even though I have more than enough pods, etc...in the 90 with a sandbed when I think back on it, it seems that there was actually more. I had always thought that it was due to the accumulation of detrius, but now I'm wondering if it's also because of the grain size?

Maybe it would be a good idea to put some cc in the refugium side?
Just a thought...

 

[Anonymous]

Sure, you don't need much, just a thin layer so the bugs have someplace to crawl around and do their thing...
Jim

 

[MiltonP]

Jim, Thanks for the info. I will be using either 'Sea Floor' or collected sand which my LFS recommended for my purpose. If the grain is to small, I will mix in some crushed coral on the top layer.

Considering that the tank is going to sit a long time with no fish, how long would you cure the rock before adding the sand bed? I have been told by several to wait 4 weeks, then siphon/vacumn the aquarium and put in the sand bed. Sound right? The tank is sitting empty and clean now. Thanks.

 

[MiltonP]

I just went for the medium CPR Aquafuge on the Powerbuy forum. So that decision is made. I would like to see what is going on in there but several folks here recommend 24/7 lighting. The tank would probably look better and be less stressful with a background anyways. Any feelings on this?

 

[Reef Guy11]

I have just one Question on copepods what are they, and what do they look like. Are they like real small shrimp like in a grey color. Cause if they are i have a lot of them in my overflow box, they hang out in the hair algae in there have no hair algae in the main tank just the Overflow boxes.

 

[MiltonP]

Some are supposedly considered parasites to fish. They seem to thrive in live reefs with sandbeds. Many of the Nano reef folks mentioned that they were thriving in their Nanos and Picos and refugiums. Jim, a few messages up, was the first to mention specifically feeding the copepods. It seems to me that a predator safe zone and algae are the keys. I am guessing that excessive skimming hurts further down the food chain, ie..the food for the algae.

Copepods are the live food of choice for the Dragonets, ie...Mandarins and Scooters, other faster predators, and filter-feeders. Probably anything that eats newly hatched brine would favor some form of pods.