What's a good star and urchin for a 20G?

dntx5b9

New member
I have a 4 months old 20 G FOWLR setup. I have a clean up crew, 3 fish, a condy anemone, a feather duster, and coral banded shrimp. I want to add a star and a urchin. What would be good candidates? Thanks!
 
Too much, already? I do 20% water changes every two weeks. I did a water change a week ago, and I just checked the nitrate level, and it's ~5ppm. Is that still too much bio load?
 
Nitrates are not the only issue to consider. Oxygen is another very BIG consideration. So is having a bit of a "safety zone" built into the system in case of electrical failure or some other situation beyond your control.

The whole idea is to have a system that is loaded in a way that an electrical failure will not immediately cause oxygen deprivation and NOT to have a system that is constantly "teetering on the brink of disaster".
 
So, what about corals then? Corals add bio load, don't they? I see lots of people with lots of corals in nano tanks. I would eventaully like to add some corals. Or corals don't count towards bio-load?
 
Corals do add to the bioload, but not in the way fish do. Many have photosynthetic properties, which means that they may actually produce rather than use oxygen. Also, they produce little to no waste, and some (like Xenia) have been shown to absorb excess nutrients from the water.
Frankly, starfish and urchins don't add a whole lot to the bioload either. A serpent star would be a good addition to your cleanup crew (but you might not see him much).
HTH,
Mariner
 
<a href=showthread.php?s=&postid=6493897#post6493897 target=_blank>Originally posted</a> by dntx5b9
Too much, already? I do 20% water changes every two weeks. I did a water change a week ago, and I just checked the nitrate level, and it's ~5ppm. Is that still too much bio load?
Hey dntx5b9,

The bad news for you is that 5ppm nitrate is actually too high. How much too high you ask....well it is recommended that you keep your nitrates below 0.2ppm. So at 5ppm, your nitrates are 25 times higher than the recommended maximum. A 20% water change will bring your nitrates down to 4ppm, which is 20 times higher than recommended.

For more information on recommended water parameters and water changes, check out the excellent articles by Randy Holmes-Farley in Reefkeeing Online.

Now, let's talk about your bioload. You need to appreciate that you have a small tank. The biggest problem with small tanks is that it is very difficult to get the right balance of biodiversity. You cannot add many of the standard fish that people use to control problematic algae and aiptasia (tangs and copper banded butterflies, for example). Also, a seemingly benign organism in a large tank can reek havoc in your tank. You must choose your organisms carefully and with purpose.

So, let's take a look at your current organisms:

1.) "3 fish" Okay, what kind of fish do you have and what are they doing for you. Three fish is a lot for a 20 gallon, but you can get away with it if you choose the right fish. My philosophy is that in small tanks, a fish must earn its keep. My 25 gallon is home to 2 fish: an oscellaris clown and a lawn mower blenny. The clown was a mistake, but the blenny was a good choice because it continuously grazes on algae and diatoms. Have you made good or bad choices for your fish?

2.) "a condy anemone" FACT: anemones have a lifespan of hundreds of years in nature. FACT: I have NEVER seen an example of an anemone thriving in a small (less than 30 gallon) tank for more than a couple years. You must FEED anemones for them to survive. Of course, they do get some nutrition for photosynthesis, but they NEED PROTEIN. It is very difficult to feed anemones appropriately and maintain good water parameters in small tanks. IMO, anemones are poor choices for small tanks.

3.) "feather duster" This is fine, as long as you feed regularly with phytoplankton. Otherwise, your feather duster will eventually starve and die within a year. I highly recommend daily feedings of either DT's phytoplankton or Phyto Feast live phytoplankton.

4.) "coral banded shrimp" These guys are highly effective predators . I strongly recommend that you minimize the predators in a small tank as they will rapidly exterminate your microfauna. Get rid of it.

5.) "clean up crew" Ahhh... the ever popular clean up crew. The standard recommendations for clean up crews are highly controversial. I recommend 1 to 2 snails herbivorous snails per 10 gallons and NO hermits.

So, back to your original question: "I want to add a star and a urchin. What would be good candidates?" I recommend that you read Dr. Ron Shimek's article on urchins and Anthony Calfo's article on starfish. My experience is that urchins often quickly outgrow small tanks. Small brittle stars can be great scavengers and definitely have a place in small tanks.

Bottom line: you can be very successful with a small tank, but it requires a lot of careful planning, patience and thought on your part to choose appropriate animals.

Good Luck!
Quinn
 
I like asterina starfish. They are small and reproduce.

In a 25, I have a tuxedo urchin. Great creatures to watch. But, they eat coralline and I have other tanks that I can cycle live rock in for it.

Best of luck,

Roy
 
Mighty Quinn, thanks for taking your time to analyze my tank. Holy cow, my tank sounds like a total disaster.:eek1: By the way, my three fish are two false clowns and a firefish (goby). Man, how do you even test for that little nitrate level? I have AP nitrate test kit, and telling the difference between 5 and 10ppm is a challenge. Forget .5 ppm!

Anyhow, thanks for your comments, and I will hold off on adding anything to the tank and will monitor how things are going.
 
Hey dntx,

I had a 20 gallon (before upgrading to a 60 gallon) for three years. I had a condy that was beautiful for that entire duration until one large bristleworm got the best of him. I never had an urchin in the 20, but I did have a marble sea star who also lasted (and flourished no less) for the duration. I also kept button polyps, a small pagoda cup coral, and a small three polyp candy cane. I never had any problem with overload (I had about five small fish, too). Sometimes the rule of thumb only depends on your system and your process. If you think your system (and you) can handle it, a marble or possibly a sand sifting star (if you have sand bed and it's small) will work. I've had a tuxedo urchin for a while and he hasn't gotten any bigger as far as I can tell. Hope that helps, sorry for rambling.
 
A bristle worm, no matter what size would not kill a Condy.

Disregard what sarabrookes said about the sand sifting star, the star will definatly perish in a tank that size.
 
The bristle worm was found in the anemone after it died, still eating the shaft. If you're going to post criticism, go ahead and try the contructive kind, too!
 
If you meant "got the best of him" by "ate it's mortal remains", yes that could be true, but the way you wrote it implied that the bristle worm killed and then consumed the anemone.

I will be constructive, if you stop suggesting creatures unfit for other peoples tanks. There is no way a "sand bed" for a 20g FOWLR can provide enough fauna to feed a sand sifting star.
 
<a href=showthread.php?s=&postid=6512258#post6512258 target=_blank>Originally posted</a> by dntx5b9
Mighty Quinn, thanks for taking your time to analyze my tank. Holy cow, my tank sounds like a total disaster.:eek1: By the way, my three fish are two false clowns and a firefish (goby). Man, how do you even test for that little nitrate level? I have AP nitrate test kit, and telling the difference between 5 and 10ppm is a challenge. Forget .5 ppm!
Don't beat yourself up too much. I don't think that your tank sounds like a disaster, but you do have quite a load for a small tank. Like I said, small tanks are tough to stock appropriately and I generally recommend limiting predators as much as possible. My recommendations for you are actually pretty minor:

1.) Donate your anemone to a friend or colleague with a larger tank. Another thing to consider with anemones is that they are mobile and that they can sting and kill corals. There are many stories of an anemone "going for a walk" one day and leaving a path of destruction in its wake. In a large tank, there may be enough room to accommodate these unpredictable wanderings, but in a small tank they can be devastating. Give your tank a good year to mature without an anemone. If you want one later on, you can always add one.

2.) Same with your shrimp and most of your hermits. I think that Shimek once said that the average density of hermits on a natural reef is about 1 crab per square meter. Hermits are not strictly herbivores. They will essentially eat anything that they can get into their mouths and will strip your rock and sand of most of the infauna. Same is true of most crabs, with the possible exception of emerald crabs, although, I think that the jury is still out on these as well.

3.) Go ahead and keep your fish. I think that those firefish gobies are prone to jumping out of tanks, so you may want to put some sort of eggcrate or other barrier over the tank to prevent this from happening.

4.) Be sure to keep up with your phytoplankton additions. This will benefit a variety of organisms in your tank, including your feather duster. Many of the infauna in your rocks and sandbed have planktonic life stages that require phytoplankton to survive. Through daily phytoplankton additions, you will help increase your infauna population, which will reproduce and put more zooplankton into the water column, which will help feed your corals.

5.) Add a couple, small "starter corals". Xenia is a good choice because it does not require direct feeding, is relatively fast growing and is not aggressive towards other corals. If, after a couple months, your Xenia appears to be healthy and growing, try one or two other corals that are appropriate for your tank. Go slow, and watch everything carefully.

6.) Watch your nitrates and endeavor to keep them as low as possible. LaMotte makes a nitrate test kit that will get you down to ~0.5 ppm nitrate.

7.) Have fun!

I hope this helps.

Best,
Q
 
<a href=showthread.php?s=&postid=6557197#post6557197 target=_blank>Originally posted</a> by dntx5b9
I am thinking about adding some sort of blenny to control by green hair algae. Any thoughts?
I have a lawnmower blenny in my 25 gallon along with one clownfish. The LMB does a really good job of eating algae and diatoms off of the rocks. I think that a small one would be suitable for your tank, but only if you get rid of some of your existing fish.

Before you buy an LMB, you should be aware that many people report problems keeping these fish long term. Do a search on Reef Central on these fish and you will see what I mean. The typical scenario goes something like this: the LMB is added to a new tank and it quickly begins eating algae off of the rocks and glass, but does not eat any fish food. Eventually, the LMB stops eating algae in the tank and starves to death.

This scenario occurs a lot with this fish. I think that the primary reason for this is that the algae growing in our tanks is not diverse enough to supply the LMB with sufficient nutrients. In other words, the fish is forced to eat the one or two types of dominant algae in your tank, and eventually becomes sick, loses its appetite, and starves. If you want to avoid this scenario, the trick is to get the LMB to accept more nutritious food to supplement the algae that it eats in your tank.

When I introduced my LMB to my 25 gallon tank, it was very shy. It would never come out and eat if I was standing near the tank. Over the course of a few weeks, it became bolder and would graze on the rocks and glass while I watched up close, but still would not eat any food that I fed to my clownfish.

After reading so many threads about how these guys start out fine, but lose their appetites after a few weeks or months, I decided to take some preventative action while my LMB still appeared to be healthy and eating. I purchased a package of Ocean Nutrition Marine Algae Seaweed Selects and a food clip with a suction cup. Once or twice a week I will break off a few 2" pieces of the seaweed sheets and clip them to glass near the LMB's favorite hiding spot. The first time I did this the LMB completely ignored the food and I removed it after a couple days. However, on the second try the LMB discovered it and LOVED the stuff. It still grazes off of the rocks and the glass, but will periodically come back to the food clip and tear off a piece of seaweed. I think that using these seaweed sheets is an excellent way to supplement the LMB's diet and insure that it stays healthy, especially during the first few months after it is introduced to a new environment (i.e. your tank).

I have had my LMB for about 5 months now. About six weeks ago it started to eat the food that I feed to my clownfish. Now, it is just as bold as the clownfish during feeding time. My LMB appears to be fat and healthy and still continues to graze on the rocks.

Bottom line: I think that many of these guys don't make it because they become undernourished and eventually lose their appetite and starve. LMB's like to graze, so giving them something that you know is nutritious to graze on is very important.

Hope this helps,
Q
 
I have to disagree with some of the comments regarding the 20 being "a disaster waiting to happen."

First of all, a nitrate reading of 5ppm in a FOWLR is just not that bad. Ideally it should be as close to 0 as possible, but the fish he has in his 20 will do fine with nitrates that "High." Even if he added some hardy soft corals such as xenia or 'shrooms 5ppm (nitrate) wouldn't be that bad.

Second - Well, I only cruised through some of the responses so I may have missed this, but I don't think anyone suggested increasing the water changes. IMO doing a change of 3 gallons a week would improve the nitrate situation and result in more stable water conditions overall.

Third - No one believes that a CC star would do alright in that tank? As long as it was fed 3-4 times per week I think it would do fine. Mine has done well so far. I target feed the star a variety of foods 4 times a week.

Why should he get rid of the shrimp? Maybe I missed something here... small bio-load, scavenger... I'm not sure what the downside is to having one CB shrimp in a 20 gallon tank. I will agree that there is a possibility of it becoming a PIA later as these guys can become aggressive. If this is what you are trying to avoid then I can see recommending ditching the shrimp.

Finally, add some macro to the tank (if you don't have a sump/refugium) to help add oxygen and soak up some of the nitrates. Chaetomorph is supposedly the best, but there are others. Prune it weekly and voila - instant nutrient export.

As for the urchin... more trouble than they're worth in a small tank. You're rocks will soon be naked and they tend to bulldoze coral frags. Again, just my 2 cents.
 
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