The corals don't like the Blenny
Hi,
<Hi Lisa!>
I got a rock with a few orange/purple Ricordea and another with green  star polyps about 1 1/2 weeks ago. They were doing great until I got a  Sailfin blenny. He climbs all over the rocks and occasionally the  corals. He knocked the Ricordea rock over 2 times!
<Hee Hee!  Very normal Blenny behavior.  They don't seem to care much what they "climb" over or perch on, and in fact, mine will forcibly throw objects off of his favorite perch!>
The first time he  just tapped it and they seemed fine, 2nd time it was flipped and  sitting on one of the shrooms. I finally got some glue but when I  picked up the rock I realized the Ric was only partially attached to  the rock. It also has a small chunk missing, the purple looks grayish and the mouth does too.
<Gluing or otherwise attaching corals is a wise choice to prevent such falls.>
Is it dead or injured? Anything I can do to  save it?
<It sounds like it is a bit  bleached.  It should recover quickly and completely if you prevent further insults.>
As if that's not enough trouble from the blenny, he's also upset the  GSP. They were 1/2 closed up after the first day w/the blenny, now  they've been closed solid for 2 days. Are they OK? Will they get used  to him?
<It is normal for GSP's to periodically close for a while.  If you are sure it is the Blenny, they may adapt, but it is probably best to move the GSP's out of his territory.
Thanks,
Lisa Spencer
<best regards!  Adam>

Potters Angel <Lawnmower Blenny and Catalina Gobies> in Possible Danger Related to Lack of Research.
Howdy!
<Hey there!>
    I'm not sure where to start, so I'll start from the top and be very verbose (my apologies)....
<No apologies my friend.>
    2 months ago I set up a brand new "NanoCube 24" by JBJ (24 gal) with about 30 pounds of live rock, and 2 bags of live sand.  The rock came from a friends 75gal, which he had for 6 years.  There is about 16 gal of water in the tank (at a guess) and it has been doing fantastic.  
<OK.>
I let it cycle for about 3 weeks, then inserted my test pilot, a small Yellow Tail Damsel, who also did great.  
<Not the most ideal means of cycling a tank.  Please read here for future reference:  http://www.wetwebmedia.com/estbiofiltmar.htm  >
The following week, the insanity overtook me, and I had a trio of Catalina Gobies, 5 different button corals, and few very pretty mushrooms delivered.
<Mmm, yes, insanity and impatience.  My, this is not a good mix.  Catalina Gobies (Lythrypnus dali) are a cool water species, preferring water temps between 64-71 F.  
Please read here:  http://www.wetwebmedia.com/lythrypnus.htm
Your corals are found in tropical waters.  An appropriate temperature would be around 78-79 F.>  
The mushrooms were in baaaad shape, most having detached from their strata and curled into spit wads.  
<Is that the technical term?>
Currently, 1 is doing great, 2 are doing ok, and the other 2 are losses.  
<See temperature suggestion above and below.>
The button corals have their days where they are wide open, and their days where they are partially open....
<See temperature reference above and below.>
     At this point, all of the fish were doing great.  Some hermit crabs and snails were added to help with some algae, eventually swelling to 16 crabs (tiny blue legs, zebra, Scarlets, and some normal Mexican red legs), and about 12 snails of various kinds (the Turbo snails will be exiting the tank in a day or 2, due to their constant tossing of my corals).
<A lot of crabs and too many snails for such a small system.  High likelihood of starvation for the snails.>
     2 weeks ago I inherited a Lawnmower Blenny from a friend, and he too is doing well, though I have never seen a blenny swim freely so much...  
<He's probably hungry.>
He seems to eat well, and everyone gets along.
<The minimum recommended tank size is 55 gallons for a Lawnmower Blenny (Salarias fasciatus).  The Blenny may starve in systems that are not well established or have insufficient algae growth.  Your system is too small and too new to be an appropriate home for this fish.  I would try to find a more appropriate home for this fish.>
A small peppermint shrimp also came with the blenny.
<OK.>  
    4 days ago, my girlfriend heard me say "That is a beautiful fish.  I wouldn't mind getting one at some point, like when I have a 75..."  at which point she wandered off to look at the puppies.  When I got home from work the following evening, she surprised me with that beautiful Potters Angel acclimating in his bag in my 24!  I was delighted, yet also totally freaked out.  I called the pet store, and they wouldn't take him back.  Now, they had him for 2 months, and he has done better than any other Angel (save a little Eblii they had).  I took about 2 hours to acclimate him, and during the transfer from bag to tank, my dog barked, which surprised both me and the fish.  He became tangled in the net due to that gill spike, and it took me about 2 minutes to extricate him with very small scissors snipping the net.
<Aye!>
     Since then, he has been very active in the tank, and was nipping at the glass, rocks, and strands of algae the very next morning.  I've recently done a profusion of reading, and I am in fear that he won't last in my little 24.  So far, he seems very happy, but only eats off of the rocks, and occasionally nibbles at the dried seaweed I clip in.  No one chases anyone around, and it is a very peaceful tank with everyone mingling and swimming about, including the Potters.  I change out about 2-3 gallons every 3 days, using RedSea for my salts. and the daily temperature beings at 72*F in the morning, at is usually at 75.5*F in the evening when I turn off the light.  
<This water temperature and its fluctuation is less than ideal for your system, best to keep temps stable and warmer, 78-79 F.>
I've been able to keep "perfect" water quality, with almost nonexistent Nitrite and Nitrate, and the KH is at the optimum level.
     My question is... what can I do to keep this fish happy and alive?  
<Actually the Potter's Angel (Centropyge potteri) is the most appropriate fish you currently have in your tank.  I would try offering some well-rinsed frozen foods soaked in Selcon several times a day.  The problems lie with the Blenny and Gobies. Your system is not an appropriate home for either.  The gobies do not belong in your system.  They require a cool water setup.  The gobies need to be relocated to an appropriate cool water home.  The blenny should be kept in a larger more established tank.>  
I've called a few stores in the area, and the only one willing to take him off of my hands will only take him for free.  I'd hate to break my wonderfully misguided gals heart by giving her gift away, and I do like the Potters so....
    Any advice or help would be GREATLY appreciated.
<Your girl seems to have done more homework regarding appropriate choices for you system than you have my friend.  She is not as misguided as you may think.  Her selection is more appropriate than your selection of a Lawnmower Blenny and Catalina Gobies.  Your water temperature should be higher and more consistent.  You have too many snails and quite a few hermits which will compete with the angel for algae.  Please do more research before making purchases.  The lives of these amazing creatures are solely in your hands.  You may want to consider a book by Robert M. Fenner titled "The Conscientious Marine Aquarist" to help you on your journey.  I think you will find it most helpful.  It is a book I continuously reference.  It is money well spent.      
  Thank you,
  Darby
<Welcome.  -Mich>

Re: Potters Angel <Lawnmower Blenny and Catalina Gobies> in Possible Danger Related to Lack of Research.
Mich,
    Thank you very much for your advice.  
<Hello Darby!  You are quite welcome!>
Doing research can be so very frustrating because there are so many contradictory sources out there, especially the people in the shops "who know" and urge you on to get things going quickly.
<Yes, it can be a big challenge, but doing your own research is essential to be successful in this hobby.  Shame on shops who encourage quickness... the antithesis of appropriate.>
     I may have found a home for the Lawnmower Blenny, and a good number of the snails will be making an exit this evening.  
<Very good, as long as they are going to appropriate homes.>
I'll continue to look for some place for the Catalinas, as I'd hate for their lifespan to be shortened on my account.  
<Yes, a shame these fish are occasionally sold as tropical species to well intended folks as yourself.>
Perhaps I should set up a second tank ( I have a 10 gal that could be used for that, but it would be too small, except for a refugium).
<This might be a good temporary solution.  Where they are at now is too warm.  The issue here really is temperature.  In many places in the world this system would require a very expensive chiller.  If you are in a Northerly climate, there is a possibility, but these fish like it as some would say, cool, I would say, brrr... cold.>
    Another question, if you don't mind:  How can I keep the water temperature from fluctuating, without heaters or chillers?  
<Mmm, you need a heater if you're keeping tropical fish, my friend.  These are quite affordable, tiny ones are less than $10 and super deluxe go for around $50.  I am shocked that you don't have one.  Go get one ASAP.  And while you're out, stop at your local bookstore and pick up a copy of "The Conscientious Marine Aquarist" by Robert M. Fenner.  This book will be a tremendous resource for you.  I reference it frequently.  It is money well spent and you will use it as long as you are in the hobby.>
I keep my house at a constant temp, so I can only theorize that it is the lighting system raising the temp, which I was assured that the Nanocubes were immune from.  These little systems don't leave very much, if any, room to add systems...
<Yes, an inherent problem, but add a heater please.>
thank you again,
Darby
<Welcome!  Mich>