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

[Mighty Quinn]

Hi Monkeyfish,

I have addressed some of your concerns below:

<a href=showthread.php?s=&postid=6568892#post6568892 target=_blank>Originally posted</a> by Monkeyfish
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.

Sure, 5 ppm nitrate is not that bad; however, I wanted the original poster to realize that this value is not "great", or even "good". He seemed to be under the impression that 5 ppm was fine, and I wanted to point out that he should be trying to reduce the nitrates. I realize that FOWLR typically run with higher nitrates, but notice that he has an anemone and wants to add some corals. Therefore, I concluded that he working towards a reef tank and not a FOWLR.

<a href=showthread.php?s=&postid=6568892#post6568892 target=_blank>Originally posted</a> by Monkeyfish
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.

It was recommended that the original poster read the articles by Randy Holmes-Farley on water changes and nitrates. The links to these articles are provided. Water changes do surprisingly little to reduce nitrates.

<a href=showthread.php?s=&postid=6568892#post6568892 target=_blank>Originally posted</a> by Monkeyfish
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.

I do not think that chocolate chip stars are appropriate in reef tanks. They are known to eat sessile inverts such as corals and sponges and are generally not recommended. Dr. Shimek's book lists them as a not recommended species and he stated in a recent post that they generally have a high mortality rate in aquariums:

I think the stars are imported now mostly for folks that keep Harlequin shrimp (as the shrimps eat the stars). One can maintain the stars for a while, but they generally die in within a few months, and they may raise havoc in a tank before they go. Sorry.

<a href=showthread.php?s=&postid=6568892#post6568892 target=_blank>Originally posted</a> by Monkeyfish
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.

Actually, I was concerned about the impact of the shrimp on the sandbed and rock critters, but your point about these guys becoming aggressive is also very valid. While these shrimp are effective scavengers, they are also effective predators and will destroy the infauna population in the sand and on the rocks in a tank this size. Small tanks typically suffer from massive over predation. Certainly, he can keep the shrimp, but he needs to be aware of the consequences.

<a href=showthread.php?s=&postid=6568892#post6568892 target=_blank>Originally posted</a> by Monkeyfish
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.

Great suggestion. He can use a plastic food clip to attach a ball of chaetomorph to the side of the tank.

<a href=showthread.php?s=&postid=6568892#post6568892 target=_blank>Originally posted</a> by Monkeyfish
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.

I tend to agree. I love urchins and they are great algae grazers, but in a small tank they tend to rapidly consume all of the coraline algae.

Q

 

[dntx5b9]

So even if I feed the shrimp daily, will it go after snails and destroy the infauna?

As for the urchins, I have so much green hair algae, I wouldn't mind seeing my rocks naked for a while....

 

[Mighty Quinn]

<a href=showthread.php?s=&postid=6573323#post6573323 target=_blank>Originally posted</a> by dntx5b9
So even if I feed the shrimp daily, will it go after snails and destroy the infauna?

I suspect that feeding him daily would reduce the amount of predation, but that kind of defeats the purpose of having a scavenger. If you are really, truly, in love with this shrimp, then by all means keep it and try to keep it well fed. Just be aware of the potential down side of this animal in a small tank.

<a href=showthread.php?s=&postid=6573323#post6573323 target=_blank>Originally posted</a> by dntx5b9
As for the urchins, I have so much green hair algae, I wouldn't mind seeing my rocks naked for a while....

Yeah, I think that you would do well to harvest some of that algae yourself. You have a small tank and it would be relatively easy to clean this rock yourself. Siphon out about 3 gallons of tank water into a 5 gallon bucket. Take a piece of rock out of your tank and gently remove the algae with a soft bristled tooth brush. Rinse the rock vigorously in the bucket water before putting back in your tank. Repeat as necessary until all of your rocks are clean.

The purpose of this exercise is to remove sequestered nutrients in the algae, and detritus that may contribute to your nitrate problem. You may need to repeat this process weekly, but eventually you should get your nitrates and algae problem under control. I think that adding some chaetomorph macroalgae to your tank would help a lot as well.

As for the urchins, be sure that you read through Shimek's article on Reefkeeping Magazine before getting one. Also, I recommend that you buy the smallest one you can find, because they can grow really fast given sufficient food.

Don't forget those daily phytoplankton additions for your feather duster and other critters.

Q

 

[Monkeyfish]

Mighty Quinn is 100% correct about the starfish I previously mentioned (mea culpa). Chocolate chip starfish (protoeaster nodosus) are NOT reef safe. They will eat corals, sponges and even anemones. If you are going to change your tank to a reef then I would definitely avoid sea stars of this type. However, I have had one in a 20 gallon FOWLR for almost a year (he'll be going into a 75 next month) and though I do not consider this to be a success YET, I think that with careful husbandry the star will do fine for many years to come.

As for water changes not being useful in nitrate reduction... this is a direct quote from the above linked Holmes-Farley article:

"In this case, it is very clear that water changes can usefully limit the nitrate concentration. Presumably, this sort of situation is the driving force behind water changes in many fish-only aquaria where nitrate buildup is a major concern, where the other nitrogen export methods are not as often used as in reef aquaria, and where especially low nitrate levels may not be as critical as they are in a reef aquarium. Clearly, larger water changes are much more effective than smaller changes for a fixed number of such changes."

My understanding of chemistry is quite limited so if I'm missing the point I'd appreciate further elaboration. Mind you I'm only looking at the section of the article that deals with nitrates. The original poster stated that he changes 2 gallons every other week. I still believe that more frequent and larger water changes would be beneficial both for nitrate export and a variety of other reasons. In regards to the nitrate reduction - I agree that water changes are a band-aid and not a permanent solution, but in the short term they are a benefit for nitrate export.

I agree with the suggestions that the hair algae be manually removed. While a pain in the butt it's not that difficult.

Hair algae typically means too much nitrate and phosphate in the water. Do weekly water changes, feed less, filter better (maybe add rowaphos or Phosban to the filtration), add macro algae and be careful when dosing phyto - this can lead to a lot of problems if done to excess - too high nutrient content in the water which results in high nitrates, phosphates and the growth of nuisance algae. If you are going to dose phyto I suggest using live phyto products instead of the Kent type additives which contain dead phytoplankton.

 

[Mighty Quinn]

<a href=showthread.php?s=&postid=6574915#post6574915 target=_blank>Originally posted</a> by Monkeyfish
As for water changes not being useful in nitrate reduction... this is a direct quote from the above linked Holmes-Farley article:

"In this case, it is very clear that water changes can usefully limit the nitrate concentration. Presumably, this sort of situation is the driving force behind water changes in many fish-only aquaria where nitrate buildup is a major concern, where the other nitrogen export methods are not as often used as in reef aquaria, and where especially low nitrate levels may not be as critical as they are in a reef aquarium. Clearly, larger water changes are much more effective than smaller changes for a fixed number of such changes."

True, but this quotation refers to the case where the tank starts out at a very high nitrate concentration, 100 ppm. In this situation, water changes can make a big impact on the nitrate levels. However, take a look at Figure 8 in the same article. In this situation, the tank starts at a nitrate level of 0 ppm and increases at a rate of 0.1 ppm per day. Certainly, the water changes help to mitigate the increase in nitrate, but even at 30% per month the nitrate increases to ~10 ppm after about 1 year. In this situation, water changes are not going to help you get to 0.2 ppm.

Perhaps I was a bit too cavalier with my statement on water changes. I definitely perform water changes in my tank, 30%-50% per month, and I believe that they are useful in helping to control nitrates...just don't expect miracles. In general, water changes alone can only reduce the rate at which the nitrate levels increase. You need to have some other mechanism to export nitrate if you want the levels to go down in the long term.

In retrospect, your recommendation for increasing water changes to 3 gallons per week is quite valid:

<a href=showthread.php?s=&postid=6574915#post6574915 target=_blank>Originally posted</a> by Monkeyfish
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.

I agree. This is a good place to start.

Q

 

[dntx5b9]

Just for clarification, I change 5 gallons every other week.

 

[Mighty Quinn]

<a href=showthread.php?s=&postid=6573323#post6573323 target=_blank>Originally posted</a> by dntx5b9
As for the urchins, I have so much green hair algae, I wouldn't mind seeing my rocks naked for a while....

If I were you I would skip the urchin. Trade the firefish goby for a lawnmower blenny. Follow the instructions from my previous thread on how to get these guys to eat.

Q

 

[sjvl51]

Concerning water changes, I found this article excellent at explaining the effect of various amounts of water changes - http://www.advancedaquarist.com/issues/april2004/short.htm The thing to remember with this article is that they are discussing a one time addition - "Consider this hypothetical situation. You are cleaning up around the tank, when someone walks by and accidentally spills a cleaning solution into your tank."

Here you are talking about nitrates being added on a continual basis. To have no effect, you must remove as much of the nitrates as is being added. To reduce the amount of nitrates in your tank, you must remove the amount that is being added plus more.

You said "I change 5 gallons every other week." It may be advantagous to change 5 gallons every week or even twice a week until you nitrates are less than 0.2 ppm. Then start increasing the time between water changes until the the nitrates start to climb. Then you will have a good idea how often you must change your water to keep the nitrates where you want them.

Vickie

 

[Mighty Quinn]

<a href=showthread.php?s=&postid=6573323#post6573323 target=_blank>Originally posted</a> by dntx5b9
So even if I feed the shrimp daily, will it go after snails and destroy the infauna?

Ok, I did a quick search on coral banded shrimp on RC. Here are a couple quotes that should convince you that these guys are bad:

from Dr. Ron Shimek:

<a href=showthread.php?s=&postid=6263014#post6263014 target=_blank>Originally posted</a> by rshimek
Hi,

They are highly aggressive shrimp that will eat anything they can catch. They can and do eat fish (they catch them at night) and they will destroy the fauna in a live sand bed. Other than these minor faults, they are great in reef tanks. :twitch:

from SMP:

<a href=showthread.php?s=&postid=6508518#post6508518 target=_blank>Originally posted</a> by smp
Why is my coral banded shrimp such a bastard?!!!

He attacks EVERYTHING.
I think he killed my emerald crab some time ago and I'm more and more sure of it all the time.
I put my hand in the tank .. pinch pinch!!
I feed my anemone .. pinch pinch (the anemone, he steals shrimp from it, I know this is normal)
Fish gets too close .. pinch pinch!!
Introduced a serpent star the other night .. pinch pinch!!

He runs around owning the tank!

Convinced yet?

 

[dntx5b9]

Wow! I had mine for three weeks now and all he does is hide. Never ventures out. He seem too scared or something. But may be I will return him...

 

[racrumrine]

I have never had one of these shrimp; so, I can't comment on them. But, many shrimp are very active at night.

If you have never shined a red light on your tank at night, you should try it. You'll probably be amazed at what you see.

In one on my tanks, I have a small pistol shrimp that I occasionally see in the night and hitchhiked on some rock I bought. Other than that, I have never seen the shrimp.

Best of luck,

Roy