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FAQs about Marine Scavenger Selection: Sea Urchins

Related FAQs: Urchin Selection, Marine Scavengers 1, Marine Scavengers 2, Marine Scavengers 3, Sand Sifters, Sea CucumbersShrimp Gobies, Sifter Gobies Marine Algae EatersHermit Crabs, & FAQs on Scavenger: Rationale, CompatibilitySpecimen Selection, Clean Up "Crews"Worms As  Scavengers, Snail Scavengers, Shrimp Scavengers, Hermit Scavengers, Crab Scavengers, Cucumber Scavengers, Serpent Star Scavengers, Seastar Scavengers, Fish/Groups as Scavengers, Losses/Troubleshooting,

Related Articles: Marine Scavengers Genus Valenciennea GobiesHermit Crabs,  

Will all get along?

Longspine Urchin (not particularly reef safe) – 06/01/13
Dear Crew,
<<Hiya Bryce>>
This is going to be a relatively simple email, but I need this problem solved.
<<Okay>>
I have a tank with a Galaxea Coral, Candycane Coral, Birdsnest Coral, and Longspine Urchin. The urchin has left every coral alone except the Candycane, which it is fond of eating.
<<In my experience, these animals will consume most any coral at times>>
I was under the impression that it was herbivorous.
<<Mmm, no…at least not in the confines of an aquarium…can be quite opportunistic>>
Could it be that the urchin is starving?
<<Possibly>>
And, if it is starving, why is it only eating the Candycane?
<<Perhaps the least noxious of the lot>>
I have attempted to feed it Nori before, but it rejected the Nori.
<<These critters will eat whatever “suits” them…and are best left to very large aquaria where their opportunistic nature may do less harm…in my humble opinion>>
Have a terrific day.
Bryce
<<And to you in kind…EricR>>

Tuxedo Urchin for 29 gallon tank 7-11-08 Hello all, <How goes it? Mike here this afternoon> I recently purchased a tuxedo urchin to help combat my growing hair algae before it became a problem. I understand that keeping my water conditions under control is the best way to combat this problem but I seem to be loosing ground and the algae is still spreading. I'm also having difficulty eliminating Cyanobacteria but the problem seems to be better under control than before. <As always, excess nutrients are the main factor here, and too little water flow with regards to the Cyanobacteria> I refuse to put any strange chemicals in my tank and I'm unsure where to draw the line with things like activated carbon. <Chemicals are not the answer; though chemical absorbents (activated carbon, and synthetics like Purigen, Poly Filter, and various phosphate 'sponges' are very helpful, and should be used. I hope you're also using a protein skimmer!> Here is some history on my tank. Up and running since end of February 29 gallon BioCube w/ stock pump, Stock lights (35 watt PC day light, 35 PC actinic, LED moonlights) Hydor Koralia #3 power head Hydor Koralia #1 power head (got this to help eliminate the Cyano) <Just make sure the flow is as random and turbulent as you can make it - laminar streams are always a bad idea> 37 lbs LR in tank 6 lbs of LR in filter (bioballs removed) 20 lbs LS Livestock 2 true percula clowns 1 orange spotted watchman goby 1 six line wrasse 1 emerald crab 1 cleaner shrimp 1 anemone crab 2 medium size brittle stars (one came as a surprise with a coral) mixed CUC of red and blue leg hermits, margarita snails, and Nassarius snails. Corals Mixed Zoas Mixed mushrooms Wellsophyllia Brain coral Frogspawn Candy Cane Bubble Coral <I like LPS too> SG 1.025 pH 8.4 amm 0 trite 0 trate 5ppm phos 0 cal 450 KH 161 ppm <All good> 7 gallon RO (maybe DI... I get the water from my LFS) water change weekly...never go longer than 7 days. <Excellent> A few months back my nitrates got up to 20ppm because I was taking water from my QT, which had high amm, trite, and trate (I made a poor assumption that the water levels were good...never assume, I know), and putting it in my display tank. I suspect this might have been the start of my hair algae issue. <Most likely> Needless to say that I immediately stopped as soon as I determined the problem. I finally got my nitrates down to 5ppm when I changed my tank over (My BioCube sprung a leak, oceanic graciously sent me a brand new tank). <They have been good to me, as well> The tank change over brought my nitrates back up to 20 ppm but other levels remain good. I did water changes every 2-3 days for a little over a week and levels finally dropped to 5ppm. <Good - keep on top of those water changes with nitrate free replacement water, and the nuisance algae should slowly recede> Unfortunately I have little money and don't have a skimmer (I know oceanic makes one for my tank but I have yet to hear if it is any good or not). <Any skimmer is better than no skimmer, and you need a skimmer> Ok I think that is more than enough background. Sorry for being long winded but all these factors I believe contributed to my hair algae. So this leads me to the tuxedo urchin. I have always liked the way they looked and when I heard they ate hair algae I thought great. When I bought him I knew he would eat coralline algae, I figured this was acceptable to a certain degree. Also most of my corals are fairly well glued/wedged in place so I thought I would take the risk on the bulldozer affect. I regularly post on a website forum and when I mentioned I had a tuxedo urchin a few people started warning me about how these guys can be an issue... got me nervous. Did I totally under estimate how much of a pain in the butt this guy is going to be? <A ~3" tuxedo urchin will slowly starve in an aquarium that size...I've seen them slowly starve in well maintained aquariums twice as big as yours due to lack of algae to eat. Miraculously, you actually received somewhat good advice from a forum. Who would have though? Reefcentral and the like are a plague to this hobby, IMO> Ultimately here is my question. Is the urchin doomed to die in my tank? I know the size is smaller than most reef owners would recommend but I couldn't find any information on what a minimum tank size for a tuxedo urchin is. Also is this cool looking guy going to just start reeking havoc on my tank? I'm wondering if I should bring him back to the LFS and just deal with the hair algae the old fashioned way (what ever that is exactly). <Avoid the urchin, for the sake of the animal's long term health> Anyway thanks for any help you can give! <Anytime. I was patient and answered all of your questions here, but realize that all of the answers to these simple questions could be found via a 10 minute perusal of our archives. Please take advantage of our search function in the future> Best regards, Sean <Anytime - M. Maddox>

Possible addition of small urchin. Algae Control 2/27/07 I have a question regarding the recent proliferation of hair algae in my system. 29 gallon 1 65 watt 10k PC 1 65 watt Actinic PC 35lb of Fiji & Tonga 3-4" of aragonite substrate Remora skimmer (produces .5 cup of dark skimmate per day), with box attachment for surface skimming, I also added some porcelain rings (can't remember name of them) for added surface area. Aqua clear 20 filter for minor mechanical filtration and added carbon filtrant. I use Tropic Marin Pro Reef Salt with my tapwater. No other additives Established for 1 year. Inhabitants include 1 lemon goby, full grown yet tiny 1 neon goby, 2 growing ocellaris clowns, can the big one ever nip! 1 Skunk cleaner 1 Blue/yellow damsel, exceedingly well behaved med frogspawn, <Frogspawn> candy coral, xenia several hermits and various snails <Too many fish in your 29, causing excess nutrients in the system.  I'd remove the damsel.> My problem started in Nov/Dec when I was putting the maintenance on my system on hold while busy finishing my basement and trying work and have a family life at the same time. Anyway, I left water changes for 6-8 weeks and only did the minimum to keep the protein skimmer clear and the water level up. In the meantime, I had the beginnings of my hair algae problem that I thought would go away once I got the parameters under control. The one thing I see now is that the particulate in the water is captured by the growing algae without hitting the filters, definitely not a bonus for keeping nitrates/nitrites down. <No, is not.  Do you have around 250-300 gpm total flow rate?  This will help keep the waste in suspension allowing the filter to capture more of it.> I do extensive physical removal of the nuisance stuff, along with my weekly water changes of 15-20%, I have also doubled my flow rate in the system with 2 more power heads. My question is due to the fact that I still don't have the algae under control, would it be prudent to add a small Egg Urchin to the fray? I am nervous about it not targeting my nuisance stuff and going after my coralline and other "good" algae. My plan was to buy one (urchin) for just the short term and I have permission to take it back to the LFS once it appears to be under control. Will it harm any of the other inhabitants like the xenia, sponges, tubeworms? Also if everything is at least worth a try, how do you remove them from the system without getting poked? Net or rubber gloves. <Definitely not a net, I just carefully pick them up with my hand.  The urchin you suggest, the Hairy Pincushion or Sea Egg is a good algae eater and, will also eat Caulerpa.  It has a habit of collecting most anything to put on its body as camouflage.  This may include soft corals etc.  The urchin will not directly harm your corals/tubeworms, but rather indirectly by it's antics.  Also read here and related links for more info.  http://www.wetwebmedia.com/nutrientcontrol.htm> Thanks again for your opinions. <You're welcome.  James (Salty Dog) Jeff Urchin... comp. & as scavengers mostly  12/2/06 Good afternoon.  <And to you, Mich here.> I recently purchased a variegated urchin (Lytechinus variegatus) at my LFS to assist in some algae control, and there were 2 color morphs, a green variant and a pink variant.  The store owner talked me into choosing the pink for it's brighter coloration, but when I brought it home, it took much greater interest in my pink coralline algae than in the green hair algae I was intending for it to help with.  I realize any urchin will likely have a taste for coralline, but does the animal coloration have anything to do with it's dietary preference?  That is, if I had chosen a green one, would I be having more luck with the urchin devouring my green hair algae?  <Unlikely.  As you know, most urchins will eat coralline along with other desirable organisms ...they are not really reef safe.> Thanks...<Welcome> Tim

Starfish/Urchins in an Aggressive Fish Only Tank  11/23/05 Apologies if you have already answered this but I couldn't find it on the FAQ section.  I have a fish only tank with a Huma Trigger, Snowflake Moray and Lionfish. I have been looking for something to control algae but the trigger keeps biting chunks or any exposed pieces from any snails that I put in there (irrespective of size). Can you keep starfish or urchins in this type of tank? And if so, would anyone have nay recommendations?  <The trigger will eat all inverts!! you better scrub the aquarium by hand!! IanB> 

My dragon wrasse, stocking, scavengers... Dear Mr. Fenner: I hope you are off to a Happy New Year! I emailed you before about my spiny box puffer, maroon clown fish, and dragon wrasse. I feed them Formula One Brine Shrimp plus. I have an ammonia tester which is still in yellow so there must not be much uneaten food. <Don't rely on just one such "tester"... the best assay of what's going on in your system is your careful observation of your livestock's' behavior...> I noticed that for the past 2 days after eating my dragon wrasse will swim upside down as if he is full. His belly appears swollen and I wondered if I should put in only 1/2 a cube instead of the whole one. <A good idea... and I would vary this diet with other meaty foods, bite-size... even "human-intended" seafood like shrimps, clams...> It seems he greedily runs to snatch away food from the clown. <Yes... a good idea to train, feed "simultaneously" at opposite ends of the system...> My puffer eats Krill-e most of the time 2-4 pieces a day. I have been feeding 1 cube of frozen Formula one and then 1/2 a cube 6-12 hours later. Should I feed only once a day? <With this mix of fishes, probably fine> I feed the Puffer 2 Krill-e at a time twice daily. I have a friend that only feeds his fish every other day. Would that be better for the wrasse?  <Yes, if it is over four inches or so in length> I read that the clown and wrasse should eat at least 2 times a day but I certainly do not want to overfeed either. <Agreed> I added 2 snails to the tank to eat algae and then I read in your book that an urchin would possibly be a better choice. <I am surprised the puffer and wrasse haven't eaten them> The puffer hasn't eaten the snails and they usually stay away from the fish. (2 turbo snails in a 55 gallon) I wondered if the puffer or wrasse would harm an urchin.  <If hungry, yes> Do urchins usually live long? My local pet shop "The Bermuda Triangle" says they only get urchins in on live rock and would save me 2 back (hopefully purple ones) but that they don't live long. What would you recommend? <Please see the various parts of WetWebMedia.com here: under "urchins", "marine scavengers"...> OK... I apologize because I know there are about a million questions here but I promised my friend I would ask one more. :) He has the purple lobster that he will give me later when I establish a new tank. It is in a 37 gallon with a tomato clown and Percula clown. He never really sees it. It hides under rocks and also doesn't seem to make tracks along the coral. He feeds it the same formula one and alternates with squid. He says the lobster has molted once and that by moving the rock, he sees it is still alive. Is there anything in particular he could do to make this world a happier place for the lobster to feel enough courage to come out and say hello? <Lower the lighting, increase water circulation, use activated carbon once a month, check the alkalinity, biomineral content of the water...> Thanks so very much for your time and patience in these matters. Any advice will be greatly appreciated. Sincerely, <Be chatting my friend. Bob Fenner>

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