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FAQs about genus Chromis Damsel Behavior

Related Articles: Chromis Damsels

Related FAQs:  Chromis FAQs 1, Chromis FAQs 2, Chromis Identification, Chromis Compatibility, Chromis Selection, Chromis Systems, Chromis Feeding, Chromis Disease, Chromis Reproduction, Damsel Identification, Damsel Identification, Damsel Selection, Damsel Compatibility, Damsel Feeding, Damsel DiseaseDamsel Reproduction

Does the presence of real or potential predators have effect? You betcha! Lutjanus mahogani (Cuvier 1822), the Mahogany Snapper.

Chasing Chromis    10/4/16
First want to tell you how much I appreciate Bob and all the crew. Got my tank 72 Gallon Bow Front All Glass single overflow in 2006, jumped in feet first with a verve and passion and no knowledge.. If I hadn't found your site I'm sure I would have given up long ago..
Tank had been down for over a year due to circumstances and life but after a 1700 mile move this summer I decided to start anew.. The most important things that I have learned from WWM are to READ, apply patience, observation and then another pinch of patience and then READ some more always much to learn/apply in this hobby..
<IF only we could have you do summat like the "Vulcan mind-meld" w/ other aquarists!>
I let the tank cycle for over 2 months while testing the parameters.. Had a nice clean cycle this time.. I have 4 Chromis and a fire shrimp small clean up crew 3 Turbos 4 red leg hermits in the tank now and parameters are Ammonia 0, Nitrite 0, and Nitrate undetectable. Salinity 1.025, PH 7.8
<Mmm; measured in the AM? I would not let this pH drift lower>
I do 15 gallon water changes once a week.. Will ride this out for a while and then start adding some soft coral around late November Quick question My Green Chromis will on occasion just before feeding start to bump mouths and extend their dorsal fins.. Aggression?
<And reproduction. Your Chromis appear to be very healthy>
Not worried for the most part they are fine one outlier from the 3 that mostly hang together.. Very much appreciate your site
Pictures attached
<Thank you for sharing Bernard. Bob Fenner>

Curious Chromis behavior; picking on branching Scleractinians       8/31/14
I have a group of seven green Chromis (Chromis viridis). One of them has been with me for several years, and the other six (very small youngsters) have been introduced this week,
<Let's hope they all get along>
I also introduced some corals, one of them a Stylophora. Today I have noticed it has been nipped. I suspected the Centropyge bicolor or the Chelmon rostratus until, bummer! I saw that one of the "little grasshopper" Chromis is nipping at it. The bites are quite noticeable.
<Mmm; yes... This Chromis species is on the larger end of the scale in terms of modifying branching corals... nipping them; essentially to open up the colony for their use, diving in and hiding>
Is this common behavior?
<Yes it is>

Should I expect this kind of trouble if I introduce more corals?
<Likely having more arborose (tree-like) species will actually help; diffuse the biting, damage>
The problem is, the Stylophora is not large.
<Perhaps a perforated cover over it for now... like a plastic strawberry basket inverted. Allowing for water, food, waste, gas movement; but keeping out nipping fish/es>
<Welcome. Bob Fenner>
Re: Curious Chromis behavior     8/31/14

> On 31/08/2014, at 00:42, "WetWebMedia Crew" <crew@WetWebMedia.com>
> <Borja>
> I have a group of seven green Chromis (Chromis viridis). One of them has
> been with me for several years, and the other six (very small youngsters)
> have been introduced this week,
> <Let's hope they all get along>
No troubles so far. They were sharing a tank at the LFS, been there for a couple of weeks and there were no damaged fins or anything other sign of trouble. Everything perfect for now, and no trouble with the hermit Chromis
who usually prefers to be in what has been its shelter for more than two years, the space between two dead Montipora plates.
<I see>
It hasn't shown any aggression towards the new youngsters (the smallest one is 2 cm long) and sometimes it chooses to join their group.
I feed a lot, so there should not be quarrels due to food :)
> I also introduced some corals, one of them a Stylophora. Today I have
> noticed it has been nipped. I suspected the Centropyge bicolor or the
> Chelmon rostratus until, bummer! I saw that one of the "little grasshopper"
> Chromis is nipping at it. The bites are quite noticeable.
> <Mmm; yes... This Chromis species is on the larger end of the scale in
> terms of modifying branching corals... nipping them; essentially to open up
> the colony for their use, diving in and hiding>
> Is this common behavior?
> <Yes it is>
> Should I expect this kind of trouble if I introduce more corals?
> <Likely having more arborose (tree-like) species will actually help;
> diffuse the biting, damage>
> The problem is, the Stylophora is not large.
> <Perhaps a perforated cover over it for now... like a plastic strawberry
> basket inverted. Allowing for water, food, waste, gas movement; but keeping
> out nipping fish/es>
At least today it hasn't touched it I think, I don't see new marks. I wonder if the two Gobiodon histrio have "complained" ;)
<Could be>
I hope to introduce more corals soon. Two years ago I had a lot of crazy growth and, suddenly corals bleached and died out. After months investigating I found two badly rusting magnets. I've been going fish only for more than a year (I didn't want to reset it because I have well established fishes that have been with me for years) and for now (fingers
crossed) it seems that the corals are doing fine.
<Welcome. BobF>

Chromis night spots, or is it something else?  1/10/12
<Hi there>
I am writing you regarding something I noticed during a "night check" in my aquarium last night.
First off, I have a 29gallon tank that is "on it's way" to becoming a reef aquarium some day.  My water quality is as follows:
1.024 Specific Gravity
Ammonia: 0ppm
Nitrite: 0 ppm
Nitrate: less than 10ppm
pH: 8.0
My stock includes:
(2) Blue-green Chromis
(2) Black Ocellaris Clownfish
(4) Turbo snails
(3) Blue-leg Reef Hermits
(1) mini Carpet Anemone
(30) pounds live rock
(30) pounds live sand
Emperor 350 HOB Power Filter
AquaC Remora protein skimmer
ZooMed t-5 lighting (24w 10k / 24w actinic blue)
Water changes are done weekly, 5 gallons per change, with pre-mixed water that I then re-mix circulate in a 5gallon bucket until the next week's change comes.
<Good technique>
My question is regarding the health of my Blue-green Chromis.  When I looked in the tank last night, I noticed that one of the Chromis had "blotches" (they appeared about the size of a pencil eraser) on his body, that were lighter in coloration than the rest of his body.  When the lights are on in the tank, this fish looks completely healthy.  Of the two Chromis
I keep, this is the larger, less dominant of the two.  The other is smaller, more outgoing and aggressive.  After reading through http://www.wetwebmedia.com/chromdisfaqs.htm, I thought that these might be "night markings" as described in one response by Mr. Fenner (I constantly refer to his CMA book.) 
<Indeed they are>
That said, I am asking the question because the more dominant Chromis does not appear to have these markings during night time hours.  I attempted to get a photo, but could not seem to snap one that was clear enough given the lack of lighting at night.  Again, during the day both Chromis appear brightly colored and outgoing in the tank.
Thank you for any guidance you can provide
Bill Hammond
<Not to worry Bill. What you describe so well is disruptive night time coloration/markings... the one more dominant fish likely showing this later at night. Cheers, Bob Fenner>

Reef Chromis vertical in corner of tank     9/27/11
Hi wonderful crew! I have three blue-green reef Chromis as part of a small, peaceful community in my 65 gallon tank. A few days ago, one of them developed the habit of spending most of its time swimming vertical, pressed against a corner of the tank.
Now a second one of them is doing the same thing in the opposite corner.
I don't see any sign of disease or parasites. They are eating. Ammonia, nitrite, and nitrate are all a perfect zero. Alkalinity is 11 dKH, pH 8.2. Is this something to worry about? Thanks!
<There may be nothing to be concerned about here, but I would be checking other aspects of water quality, observing your livestock closely... What other life is in this system? The history of recent introductions... There might be a negative reaction to some other organism interaction going on here.
Bob Fenner>
Re: Reef Chromis vertical in corner of tank
Bob - Thanks for your quick reply! I have not introduced any new livestock recently. I began stocking the tank in early spring and finished stocking it in late spring. It's been stable since then. The other fish in this 65 gallon tank are a mated pair of ocellaris clownfish,
a pair of Banggai cardinals, and one royal gramma. They all get along well. The only other major livestock are one coral banded shrimp,
<Keep your eye on this. Often become predaceous>
two skunk cleaner shrimp, and a blue tuxedo urchin. (Shoot me if you wish, but I honestly find the two skunk cleaner shrimp more interesting to watch than the fish! I could see having a tank of nothing but motile invertebrates.)
<Me too>
There is one suspicious thing happening lately. I have seen an explosion of Spirorbids.
<Mmm, unrelated... a matter of succession... the coming/going, preponderance in evolution of systems>
But I'm feeding the same food in the same quantity. Also, nitrate is zero and phosphate is under 0.1 ppm. So I don't get it. Anyhow, thanks for any advice you can give. You guys are the best!
<I strongly suspect the Chromis are reacting to your Clowns. If you have another system, I'd be moving one or t'other. Watch the tank steadily for an hour or so, or even more attentively during feeding. Clownfishes come to dominate the small volumes we keep as aquariums. Cheers, BobF>
Re: Reef Chromis vertical in corner of tank
Bob - Thanks! I'll keep a close watch. I work at home, and the tank is next to my desk, so I get to watch them for hours a day when I'm supposed to be working! I have seen no obvious signs of aggression, and at feeding time they all eat together in one group, except for the royal gramma, who keeps to his own corner and has to be fed separately. I guess time will tell.
<Ah yes. B>

Damsel fish "body shaking"? 11/08/10
Hello WWM,
So I have just recently had to restock my tank and I started out with a few damsels. The tank is cycled and has been up and running for several months, before putting the animals in the tank I had my LFS double check that all the parameters on my tank were what I thought they were (all good). So, I get 3 Chromis and one yellow tail damsel. (I think one of the Chromis and the yellow tail got into a bit of a fight as it looks like he's missing part of a fin.)
I noticed that all the fish were hanging out in the lower left, back side of the tank, an area that is pretty sheltered, so I just figured they were getting used to a new environment. Later that night I noticed that yellow tail acting "funny". It looks as though he is having a perpetual seizure, just shaking his head back and forth with lots of body twitching, this was followed this morning by two of the Chromis doing a similar type thing. I can't find any postings anywhere on this behavior.
<Mmm, likely "natural"... Pomacentrids and many other fish groups do this behavior... for signaling (territoriality), reproduction et al.>
Obviously I am worried about some sort of contagious thing here? I'm a little worried about Ick as my last batch of fish was pretty much wiped out by a Tomato Clown that I'm pretty sure had Ick, the tank was treated and a few of the fish survived, for a while. Although I do not see any of the typical signs of Ick, like the "sugar/salt" specks on fish or "flashing" behavior. This is a 20 gal system
<Ahh, very small, particularly for Chromis spp. Damsels>
with some live rock in it. Any suggestion are greatly appreciated, I just don't want to loose anymore fish. Thanks, Dylan
<Or lose them likely. Please read here: http://wetwebmedia.com/chromsysfaqs.htm and the linked files above. Bob Fenner>

And Then There Were Six, Chromis beh.  6/25/09
Hi Crew,
I recently added 7 small (3/4 inch) Chromis Viridis to my reef tank.
Then, on their second day of residence, I watched my LTA consume one.
<What they do>
He was still breathing, very slowly, as he went down. I figured that was the stupid one. ;-) Now I'm finding that the Chromis are sleeping with the LTA at night.
<Also natural... associate with stinging celled life to avoid fish predation>
Often as many as four of them in there among the tentacles. Is this common/normal/safe behavior?
<Normal yes, safe, no... Would "hang" in and about an arborose stony (likely an Acropora sp., perhaps a Pocillopora...) if you had one present>
They've plenty of nooks in the LR that they're eschewing. Maybe they know about the Stomatopod and figure the anemone is the lesser evil.
I've tried to get that darn mantis out. Traps have failed, hyposaline dips have failed. My LFS suggested leaving the rock out to dry for a couple hours, but that seems unlikely to work, in my opinion, and his
lair has some nice Porites sp. that I'd like to keep if possible. He's rather small, sub-one-inch and so far and hasn't wrought so much havoc. He walloped some hitchhiker Xanthids, but who's complaining.
I'm hoping that as he gets bigger he'll get hungrier for bait I periodically leave out.
I know, now, that the LTA wasn't the wisest addition. Purple tentacles, green and fluorescent green oral disk, about 6 inches across (on average), bright orange base. But I've noticed that he never quite closes his mouth. It's usually open about a centimeter. Is this gaping?
<Not necessarily>
He seems otherwise happy, hasn't moved since I buried him in the gravel, stands up at night and flattens out during the day. I'm a bit worried about allelopathy with the Euphyllias, Faviidae, Zoanthids, and Sinularia in there.
<Worth consideration...>
Thanks in advance,
<Bob Fenner>

Refugium <skimmer use f'), (Red Slime Algae) and ODD Blue/Green   12/17/08 Chromis behavior, Hi Guys, <Howsit Chris?> I have a 1.5 year old 110 gal reef tank with a 30 gal sump and have just added a 30 gal refugium that is cycled off of the sump via a pump that operates my UV sterilizer and gravity flows back into my sump. The problem is that I have followed many other peoples advise <advice> and taken my skimmer OFF my tank after adding the refugium and this has caused some huge NITRATE problems. <Even my friend Leng Sy, owner/operator of EcoSystem Aquarium, the originator of (Miracle) Mud filtration endorses skimmer use nowadays...> Really Bad Idea. I went from 10 ppm to >50PPM ! I know. So I researched more on your site and saw Bob's great advise is to KEEP IT ON (the skimmer that is). <Ah yes> I can verify this, keep skimming! So I added my Aqua-C EV120 back and am skimming like a madman, still high on NitrAtes though. In seven days I have changed out 45 gal of water and still have high NitrAtes though! I added a NitrAte reactor to try and reduce the nitrates will take a week or 2 to get working correctly will let you know if/how it works out. <Takes a while...> Anyway Tank Param.s are: 110 Gal 1.023 sal 78.5 degrees F 0 NitrIte >50ppm NitrAte 8.2PH 3meq/l Alk 480 Calcium 0 Ammonia <.10 PO4 4" live sand 130 lb live rock "Vanuatu" and "Fiji" mix Livestock: 7 blue/green Chromis 1 maroon clown 1 scopas tang 1 yellow tang 1 chevron tang 1 powder blue tang 1 coral banded shrimp 2 blood/fire shrimp 1 serpent star 10 turbo snails various snails and hermits Corals: 1 red bubble tip anemone 1 huge hammer coral various mushrooms and Zoanthids Question #1 Anyway about 9 months ago I battled a problem with RED SLIME algae and took a long time to get rid of, using some mix product ( I don't recall the brand) that didn't seem to work but after a month it finally did eradicate the red slime algae from the display tank. So to my question. After adding the Refugium (25 lbs miracle mud) and Gracilaria and Halimeda algae with good water flow, I started getting the dreaded RED SLIME algae in my refugium only and on the macro algae. What's the deal with that? Main tank is fine. Other than stated high NitrAtes. <Cycling in a word... succession... opportunistic Cyano... Again, mostly time going by will solve this> Question #2 Also, I have 1 of the 7 blue/green Chromis that is the largest of them all (about 3") he has started to get a really blue tail that is markedly darker in blue than his body, this is new. Also he swims into a vertical position (head up) in a specific area of the tank and scares off all other intruders. <Dominance...> Including a blood shrimp that walks over to his hang out and the Chromis nips his legs and pincers and he tries to use a mock spine in his tail to strike the shrimp (does not hurt or even intimidate the shrimp). My Chromis have learned this behavior from mimic-ing the aggressive tang behavior, <Interesting> its kind of funny watching the Chromis try and strike each other with their tails like the tangs do. I would normally think that this Chromis is a pregnant female or egg watching but I have yet to see any eggs or anything like that. What's the deal? <Summat as you say... this is reproductive behavior...> Chris Edwards <Thank you for sharing. Bob Fenner>

Blue/Grn Chromis beh.   6/4/08 My last question is about a green Chromis (Chromis viridis) in my tank. All of the Chromis except this one are very active and swimming around the tank. This one stays under a rocky shelter and only comes out to feed. On its right side is a small less than a centimeter across, zit looking thing right behind the gills. The center is red and it looks puffy. Should I give the fish a freshwater dip? <I would not... too likely to do no good... but further stress. I would just be patient here. BobF>  

Chromis Behavior with the Chromis Shrink Adam J. (Bullying?) 3-23-08 Hi Crew, <<Hello Jason.>> I'm having some trouble with my blue-green Chromis school. <<Lets see what I can do to help out.>> I have 5 Chromis in my 90 gallon (+30 sump) reef, sharing space with a golden hogfish, 2 ocellaris, lawnmower blenny, purple Pseudochromis, and a flame angel. <<Those are some potentially boisterous mates for the, most of the time, mild mannered Chromis.>> I am dithering on whether or not to remove the Chromis, but before I do, I want to seek advice on their behavior. <<We'll see what insights I can provide.>> I've had the group of 5 for almost a year. Until recently, all seemed pretty happy, but over the past few weeks, things have gone downhill. <<I am curious to know if any of the aforementioned tank mates were introduced during that time?>> They mostly hang out in the corner of the tank and don't swim around. <<A sign they are insecure with their surrounding'¦perhaps some bullying going on, either externally (from tank mates) or within the shoal itself? Any observations on your part that can attest to this or refute it?>> Worse, two of them seem to have stopped eating over the past week. <<Assuming water parameters are acceptable and that they [Chromis] are in otherwise good care/health this bit of circumstantial evidence leads credence to my assertion that there may be some psychological issues occurring, specifically bullying.>> One of them has developed a bizarre nocturnal behavior -- rapidly swimming around the walls of the tank repeatedly. <<**Insert above comment here as well.**>> Not sure what's going on. <<See above, can you lend any observations that would help me to better 'diagnose the issue.'>> The tank is well established and stable -- pH 8.0-8.2, SG 1.025, 80F, 0 NH4, 0 NO2, 7 hour photoperiod, ozone, ORP 450mV. All other fish are acting normally; my clownfish even started spawning in early February! <<With spawning often comes aggressive 'patrolling' of said breeding areas.>> I feed all the fish Pro Reef flakes once or twice a day, sometimes supplement with frozen Spirulina or Nori. <<Try something that simulated/replaces the Chromis feeing on zooplankton. Mysis shrimp or finely chopped krill/clam meat.>> None of the other fish are bullying the Chromis, though they seem to bully each other occasionally. <<You could me missing, specifically during the night hours.>> Any advice? <<Rearrange the aquascape, attempt to isolate some of the "bulliers," or if all else fails remove the Chromis. You are pretty full for a 90 gallon, at the least there is some psychological crowding going on.>> Thanks as always! <<Anytime.>> Jason <<Adam_J.>>

Second Visit; Chromis Behavior with the Chromis Shrink Adam J. (Bullying?) 3-23-08 Hi Adam, <<Hello Again Jason.>> Thanks for the prompt reply. <<We do our best.>> My intuition is that bullying is going on. <<Mine as well from what I gathered in your last email.>> I did add one other fish after the Chromis -- the flame angel. They don't seem to notice each other. In fact, the Chromis never seem to be troubled by the other fish, as they stay near the top and the others tend to occupy the rockwork areas. <<It may not be their choice that they are not occupying the rockwork.>> When feeding, the Chromis usually get the food at the top of the tank, and the others let it float down some, or they all just crowd around. The Chromis are generally passive fish, but the most aggressive eaters in my tank. The Chromis don't encroach on the Clownfish's territory, and I've never witnessed the clowns going after them (clowns sometimes scuffle with the hogfish). There is intra-shoal bullying for sure. <<Normal, hopefully the 'aggression' is spread around and not focused on a single individual.>> Two of the Chromis seem to be the more dominant, two semi-aggressive, and one completely passive. The most passive (ironically, the biggest) has not eaten much if at all the past few days. <<Try putting some more variety into their diet with the suggestions I sent you in the prior email.>> The others all have eaten when I feed, at least usually. At night, they mostly retire in a corner behind the rocks, though one is now doing the rapid swimming and another sleeps in a top corner of the tank. The bullying takes the form of chasing. <<Yes'¦an attempt to clear the aggressors territory.>> It usually does not happen when they are eating (they are too focused on eating!), but soon after the aggressives will chase the others around some. I have a 10g quarantine tank all set and empty. Should I temporarily remove the bullies or the ones that aren't doing well? <<It is certainly worth a try.>> I need to mess with my rocks soon, anyway, to catch a Zoanthid-eating crab! <<Good luck with as well.>> Thanks, <<Anytime.>> Jason <<Adam J.>>

The Chromis dance  9/1/07 Hello all, and Happy Labor Day : ) <Ah, small wonder I am laboring... and enjoying it> I was reading several articles posted regarding blue green Chromis. I currently have three in my 55gal tank, and 2 of them are acting strangely. The largest was recently chasing the middle sized one for a day and now over the last several days they have been spending a large amount of time next to one another and occasionally rub up against one another, and twitch next to each other. Any ideas? <Courting behavior...> Possible early spawning behavior. <Yes> No bite marks frayed fins etc. Thanks for your time. Have a great and safe weekend Marie Jones <Ahh, to all as well... Slow down if driving... remember, force equals mass times (relative) acceleration... and the derivatives thereof... Bob Fenner> Blue Tang and Chromis hiding, Fish Behavior 3/23/07 Hi WWM, <Hi Maison> I have a 2" Blue (hippo) Tang and 3 Chromis but every time I walk past the tank the Blue Tang and the smallest Chromis hide for about a minute or so.  This has been happening for the last week and I don't know what the problem is. I have had him for 5 1/2 months and my last fish introduced was a Convict Tang which I introduced 1 1/2 months ago. He is 3 1/2" and is great friends with the Blue Tang. <Mmm, drinking buddies, huh?> They both eat from my hand together and never fight. The tank is a 6x2x2 reef tank and this is the first time this has ever happened. If you know what the problem is may I please have your thoughts. <Behavior is not that unusual.  My False Lemon Peel exhibits the same behavior when I walk into the room.  This behavior started when I switched from PC to HQI lighting which creates much more shadow movement which can/will alarm fish. Have you changed your lighting or is your tank exposed to a bright window?  None the less, no worries here my friend.> Thank you, <You're welcome.  James (Salty Dog)> Maison

Fish injured, sick, what do I do? Chromis sys., beh. Using WWM -- 03/18/07 Dear Bob,     Hello again, this time I have a few questions for  you about my fish in quarantine. I have 2 green Chromis in two separate tanks  with two problems. The first Chromis has a large open sore on its side  stretching vertically from its dorsal fin to its pelvic fins. It almost appears  as if other fish had bitten his scales off and now there is a red open wound  left. <Mmm...> I haven't witnessed any aggression towards the little guy from any tank  mates during the day or night, until today. Some of them are picking at his  wound and his fins now. I was considering doing a Methylene blue dip with  him, would this help? <Maybe> Also I want to run chelated copper sulfate in this QT tank  would this have any negative effects on animals with open wounds? <Not likely> The  second green Chromis in the other QT tank recently had a series of dark spots  appear all over his body, almost like bruising. <There is something bothering these fish...> All of the spots are the size of  one of his scales and they are scattered all over his body, none clumped  together. Both Chromis are eating well and swimming fine. Another fish in QT (my sixline wrasse) has a sore spot on top of his head just before his dorsal fin it looks like it may have been a wound that got infected. Also at night he seems to be making a "slime cocoon" that he rests in, is this normal or should I be concerned? <Isn't atypical> What steps should I take if any? <None given what is presented here> Any idea of medications to use to fix / control the problem? My last concern is my Ventralis Anthias has white "String like" feces, and  refuses to eat, any suggestions on a way to get him fixed up? <Please read on WWM re Vermifuges, Anthelminthics> QT tanks 29 gallon / 20 gallon Nitrites / Ammonia / Nitrate all 0 Temp 78 degrees F. 5 gallon water  changes on the 29 gallon daily because there are quite a few fish in  it, and every other day on the 20 gallon. the 20 gallon quarantine tank has a mandarin dragonet, 2 ventralis  Anthias and 2 green Chromis. The 29 gallon quarantine tank has 6 green Chromis, a coral beauty, six  line wrasse, solorensis wrasse, 3 yasha haze gobys 2 small percula clowns and a Banggai cardinal.   Your advice is greatly appreciated as always. Thank you! Brian <Please learn to/use the search tool, indices... Much ancillary information to your questions, circumstances... that can't be answered, preferred expediently in this fashion. BobF> Lone Chromis... reading Chromis sys., beh. -- 03/18/07 Hey WWM Staff! I have a 30 gallon FOWLR Saltwater tank. I know this is a small tank but I wanted to be sure I was interested in the hobby before spending 3,000 dollars investing into it. (You'll be happy to know I'm very interested. ) <Yay!> After my cycling was complete I added some fish. A yellow Belly Damsel, and a Blue-Green Chromis. Around with some invert. buddies to keep the tank looking nice. (14 blue let hermits, 3 snails, and a sand-sifting star) Its been about a month since i finished adding the fish and inverts. from the QT tank to the main tank.  My Damsel is loving life and his colors have actually improved since I've had him, but my Chromis is well lets say acting "strange". <Is a stranger in a strange land, with apologies to Robert A. Heinlein... a social animal jammed into a tiny space with a bully of another species... How would you feel being placed in a closet with a cougar for a month?> The water is fine ammonia is at 0 along with nitrite, and nitrates are around 15. The PH is a little low at 8.0 but I was told Chromis are pretty much invincible. <Uh, no... Please read here: http://www.wetwebmedia.com/chromis.htm the linked files above... re Systems, Compatibility...> He has no sign of disease or illness, and eats like a champ. But often times when I come into the bedroom to watch the fish the Chromis is just sitting in the corner with his head pointed towards the light. He has been acting this way since I put him into the Main tank. Could this be because he is lonely? <In part, yes> I know Chromis are naturally schooling fish, would it be beneficial to add 2 more into the tank <Mmm, nope... tis too small> or would they bond in the QT tank and leave him out of there "posse" I would eventually like to further stock my tank  with a pair of false Percs' and if needed 2 more Chromis. Any suggestions or insight would be extremely helpful! Thank you for your non-stop patience and kindness to us newbies. :] Ryan <Wait till you have a/the larger system... and read re what you have. Your "answers" are all posted on WWM. Bob Fenner> Re: Lone Chromis  3/19/07 Hmm Well I guess I am confused, I talked with other people (from this website and the LFS) in the past and they said 30 gallons was plenty of room to keep 3 blue-green Chromis and 2 Percs. <Please... refer me to where this is posted on our site, the URL, about where positioned. Such gets by me... when I don't read through all other's responses, and am away and others are moving... I would like to amend> Those are the only fish living in the system. So Bob, your response is very different to those responses I received from your colleagues at WWM. <No shame or surprise... opinions vary. Note, above, I state "amend", not "correct">   Also I have read through 3 of the FAQ's about Chromis and none really did match my question. I took the Yellow-Belly Damsel out of the system so there should be no foul-play. <Good move> I would like to know what the minimum size requirements you would see fit for my 5 fish. <Sixty gallons... Usually a standard "15-20 gallons" per small/er Pomacentrid/Amphiprionine specimen... but the genus Chromis are more easy-going, the Perculas about the most amenable to crowding Clown...>   I'm not trying to be hostile in any way so I am sorry if this comes off a little rude. <No worries. It is my earnest desire (why else would I have spent thousands of hours of my life helping put this site together and maintaining it for free... to help others. If my statements are not clear, complete, I appreciate the opportunity/challenge to make them so> I wouldn't have been able to keep this system going without WWM's assistance. Thanks again! Confused amateur <Do please write back if this isn't understood. My input may well not "agree" with others, but I do want to provide rationale, sufficient information for people to be able to go beyond what they experience here, be capable and assured in relating to others in turn. Bob Fenner>

Mixing Chromis  1/29/07 Hello <Hi.> and thank you in advance to the Crew, <You're welcome in advance....> I have read through the FAQ's regarding the Chromis and I can't seem to find the answer to my question.  Will Chromis cyanea (blue reef Chromis) school with Chromis viridis (blue-green Chromis)? <Being very similar, they will at times "hang-out" in captive environments, I a little trouble calling what they do in captivity schooling, it's a very different behavior than that of the wild counterparts.> I wouldn't mind if they did or didn't I just don't want world war III to break out in my tank. <There could be bullying, damsels, even Chromis tend to have a social hierarchy....really depends on individual specimens, no way to be 100% sure.> My current three 1" b/g Chromis  are schooling and doing well.  I like the look of the blues and would like to add two of them if they will mix, or three of them if they will school by themselves. The only other fish are a bottom dwelling goby and blenny. <Well it is a risk, may/may not work....best to avoid if possible, but just for fun what is the size of the tank? Could/will make a difference.> Paul <**AJ.>

Chromis Acting Weird   7/8/06 Hello to all of the Crew, <And you> Long time reader. First question. We have 2 tanks a 55 gallon and 75 gallon. We established over a year. We do regular water changes and have our water checked weekly. <Best to do this yourself... samples "change" with time, transport...>   It's always fine. I try to stay on top of everything and spend time daily watching my buddy's in each tank, and so we don't have any problems.  The question is on our 55 gallon reef tank. We have 3 Chromis that have been together for a year now and the biggest one started going in the corner and acting weird. At first I thought he may have gotten too close to the Foxface. She's sweet but accidents happen. <Yes> That was a month ago and we re-checked our water and everything's fine. Well two days ago, I find one of them on the bottom in front towards the corner acting the same way the first one does. The third one is the only one going into his little place at night the other two stay in the corners.  Now this a.m. the third one isn't coming out he's staying hidden in the back. Everyone else in the tank is doing fine. Help. We have a Foxface, small Wrasse pink with yellow fin, Cardinal, 2 cleaner shrimp, lazy brittle star, hermits, snails, oh and a fat lawnmower blennies, scooter blennies. Nothing has been added to this tank. And most have been in there a year or right at a year. Any advice is much appreciated. Thanks, Tere, Eddie & our fish Buddies. <Nothing "jumps out" as a problem here... and of common issues, some of the other livestock listed would be mal-affected first. It may well be that these Chromis damsels are just "getting old"... only live a few years... Bob Fenner> P.S. We have Rat Terriers and one of them, Betsy loves to watch the fish with our grand-daughter or by herself. I think she misses dripping them in. Because we sat the 75 gallon up and she sat with each fish while they dripped. <Neat>

Chromis/Behavior  - 06/30/06 Hello Crew, <Hello Nicole> Three weeks ago, I purchased three Blue Reef Chromis (Chromis cyanae), <cyaneus> two of which died the next morning. <Unusual, these guys are almost bullet proof.  Did you acclimate?> I have one left in the QT, and he's doing great. I've read on your site that these fish usually do best in odd numbers, which is why I initially bought three. I tried to replace the two who died, but have not been able find them (Blue Chromis) anywhere. I also read that it is acceptable to mix a school of Blue Chromis with a school of Blue Green Chromis. So here's my question: should I try to introduce the Blue Chromis to a school of Blue Green Chromis, or, should I just put the Blue Chromis into the display tank by himself? Which is the best scenario for the sole survivor? <The cyaneus is of Caribbean origin while the viridis (blue/green) hails from Indonesia, Coral Sea and Tahiti.  I'm quite sure they have never met before, but since they are of the same family, chances are good the blue Chromis will buddy up with them.> <<Uh, no. RMF>> Thanks, <You're welcome.  James (Salty Dog)> Nicole

Re: Mixing Chromis?    7/1/06 Thanks for your response to my question re: mixing Chromis. <You're welcome.> Now, of course, I have a follow-up question. My Blue Reef Chromis' time in quarantine ends in just a few days (he will have been in the QT for 1 month). So if I decide to try to get him to buddy up with a group of Blue Green Chromis, should I leave him in the QT with the group of Blue Green Chromis for another month, or, should I put him in the display on his own, and then add the Blue Greens to the display after their month in quarantine is up? Which way will be most conducive to peace in the tank? Oh, and I forgot to give the tank details in my last email: 150 gallon tank; lots of live rock; 1 False Percula; 1 Lemonpeel Angel; 1 Black Sailfin Blenny; crabs and snails. <Nicole, an update on this.  Mr. Fenner indicated that they will not buddy up/school together.  You would fair better to find a couple more kids on his block to play with.> Thanks again! <You're welcome.  James (Salty Dog)> Nicole Blue green Chromis beh., sel.  - 05/10/2006 Hello. <Good evening> I have a 25 gallon tank with 30 pounds of live-rock. It has been cycled for about a month now. <OK good.> About a week ago I added 2 Blue Green Chromis fish and 1 Black and Gold Chromis. The Black and Gold Chromis stays near the bottom guarding all of the live-rock, <Somewhat normal> snapping at the other two fish if they get anywhere near him. The two blue green Chromis fish stay near the top and have gotten along so far, but today the larger of the two has been chasing the smaller one around the tank. Once the larger blue green Chromis chases the smaller one down to the bottom, the Black and Gold Chromis attacks the smaller one. What should I do to calm them all down? Should I add another Blue Green Chromis to make an odd number? Should I remove the Black and Gold Chromis? Should I add a different larger fish to calm the Black and Gold Chromis? I don't want to overstock my new tank. Thank you! <They are probably just showing dominance here.  Let them figure it out on their own - this normally works out once a hierarchy is formed.  No worries, but keep an eye on them anyway - make sure no physical damage is being done.  Have a good one, Jen S.>

Chromis Behavior   2/26/06 Hi from Atlanta! <Hello backatcha from S. Cal.> My 90 gallon reef is about 8 months old.  Inhabitants include: yellow tang, blue tang, 2 gobies, 2 clowns, 2 green blue Chromis, an old one eyed sergeant, <Named Sgt. Lucky?> orange star,  serpent star, yellow tailed blue damsel, and lg. Potters angel, <Oooh, not easily kept> an anemone, and various corals.  Everyone seems to get along well.  My question relates to the green blue Chromis.  Late in the day they tend to get very active and playful? <Me too> They swim up to each other at a high rate of speed and kiss.  Is this all in fun or what? <Fun plus... spawning, et al. behavior> One is larger and definitely dominant but never attacks the other.  Thanks in advance for any info you can share!! Katie <Keep watching! Bob Fenner> Chromis / Damsel Behavior  11/23/05 Long time reader, first time question asker... <Howdy> I have a 75 gal tank with miscellaneous corals and fish that include 2 yellow damsels and 3 blue green Chromis.  I've recently added some Ricordea Mushrooms.  After 1 month of having them in the tank, I've noticed the Chromis like to go up to them, wiggle around, brush up against them and whack them with their tails. I doubt the mushrooms appreciate this.  I've seen the Yellow Damsels do this to my Hairy Mushrooms in the past but not as intensely.  This seems a bit odd since my Chromis don't bother anything else in the tank.  What could they possibly be doing ??? Thanks, Chris <(Mis)behaving?... looking for "substrate"... adventitious behavior that might have preservation value... place/s to hide should there be a predator... Bob Fenner>

NASCAR Green Chromis  10/3/05 Dear WWM, I know you receive a lot of questions so I thank you in advance for taking mine. I am a new fish owner with a 37gal tall tank. The current inhabitants include two blue-yellow-tail damsels two green Chromis and a juvenile golden wrasse. <... too much...> All the fish get along fine with each other  and I haven't seen any aggression problems. I have had the tank about three months and it has been stable for two (all the water parameters are fine). One of the green Chromis (a resident of about a month now) has been acting strange ever since it was added. For the first two weeks it picked a place behind a large rock and stayed there not moving (except for it's fins) even during feeding times. I figured it was just stressed from the transition and just let him be. <Mmm, stressed and psychologically bullied...> One morning he was so still that I nudged him with my net to see if he was still alive. After three nudges he moved behind another rock. Lately though, he has had a new habit. He has taken up swimming around in a circle of about five inches in diameter, perpetually turning left. When I first saw this I was very excited and sprinkled a little food in the water as a reward for coming out from behind the rock. The other fish swarmed up and ate the food while the Chromis never once broke stride in his circle. Have you ever seen anything like this? <Yes> His color looks good and the eyes don't appear cloudy at all. This afternoon I took my net and placed it in the middle of his race track and instead of moving around it he swam right in, looked confused for a moment, swam out and returned to his circle. If this is something you have seen before, is there anything I can do to help him or make him more comfortable? <Mmm, remove some of the other damsels, or place all in a larger world... at least sixty gallons> Also one quick question about my golden wrasse. I looked though your Wrasse FAQ's and I noticed that they generally do a good job of cleaning out crustaceans. Is this true for my particular species of wrasse or can I add things like shrimp etc? Thanks in advance, Justin <Is this a Halichoeres species? Bob Fenner> Sending Chromis To School  9/27/05 Greetings Bob (or other WWM crew), <Scott F. here today!> I have a question about getting Chromis to school in aquariums. I have read that they will sometimes not school if they do not have more aggressive fish around. In my 95 gallon tank I currently have a 4" Hippo Tang, two Cleaner Shrimp, and about 10 Turbo Snails. I would like to eventually have 5-7 Blue-Green Chromis, a Flame Angel, Horned Blenny, and a Tomato Clown. The Chromis would seem to be the next most peaceful fish, but I don't know if the Tang would be enough to get them to school up. I was considering getting the Angel and Clown, and then adding them. Does this seem like the correct action? As always thanks for the help, Cory <Well, Cory- I think I'd stock the Chromis first. Schooling behaviour is one of those things that you cannot depend on in captivity. In other words, the fish may or may not embrace schooling behavior. I can recall vividly stocking a tank with 20 of Neon Tetras as a kid, and seeing 17 of 20 Neons schooling, while the other 3 were perfectly content to swim about alone You never can tell with fish! Get the Chromis quarantined and settled in the system first, then add the other fishes that you desire. Hope this helps! Regards, Scott F.>

Damsel in distress, Dascyllus are social animals  08/08/2005 Hi, <Hello there> I purchased a four stripe damsel five to six months ago and have had continuous problems with it ever since. When I placed it in quarantine and it always preferred hiding behind the heater or other equipment rather than the PVC pipes or the artificial branch coral I placed in there. <... Dascyllus are social species... live in groups> She has also always been a very scared fish, and always hides except at feeding time. About three days after I got the fish in quarantine dark areas started forming on the white stripes just behind the gill plates and the last white stripe on the tail. the fish has been this way ever since. By the way the fish did lose an eye while in quarantine from injury most likely while darting to a hiding place when I entered the room. I kept the fish in quarantine for an extra two weeks and administered a copper treatment because she just was not acting right. <Starting to sound like the U.S. military's confinement of folks...> The copper treatment seemed to work somewhat the dark spots became more vague, but did not disappear. <... poisoning> However, she was still a very scared fish. After a month in quarantine I moved her into a 46 gallon tank (where she still is) with live rock and numerous hiding places but she still prefers to hide in the equipment at the top of the tank except at night when she goes down to hide in the rocks. The dark areas are still present and seem to grow in darkness when stressed (during water changes and when I clean the glass). There are no outward signs or parasites, but I do sometimes see her scratching on rocks. She is the only fish in the tank. The water quality should be excellent (I use RO/distilled water) and all parameters are good and consistent. She eats and seems to be a very greedy fish and is not shy around feeding time. So my real question is what could cause all these symptoms and this extreme fear of people and movement. The best answer I can come up with is stress, but I can not find the cause. Please give me your opinion. Also would it be safe to add another fish in this tank with her in this condition. Thanks for the great service, Jed <Thank you for writing to well, thoroughly... to reiterate, the one simple fact that you apparently are unaware of is the need for others of their own kind... Take a look at Dascyllus species pix in the wild... they are always in close association with others of their own kind. Bob Fenner> Crazy Chromis! We have a 100 gallon tank that recently developed a horrible algae.  The closest we can figure is it's a brown diatom (?) algae. <Usually eradicated by using RO/DI as source water...Silicates tend to cause this problem> We have "vacuumed" the algae off of the rocks and done about a 25 gallon water change at each vacuuming.  We got another 30 gallon tank for the Chromis because they turned white, hovered straight up in a corner, and acted as if they were having seizures. <That's not good...Lots of possible causes, ranging from some water chemistry issues to an infection of some sort...Do a little research on this...> Our tank finally cleared, with little algae left in the tank, so we took everything "back home."  Much to our dismay, within six hours the Chromis were back in their corners, acting spastic.  Why are they doing this?  They are the neatest fish, so calming to the tank, (and to me,) I hate to see them this way.  This is our first saltwater fish tank, and we are definitely learning a bunch.  Any thing you can tell us would be greatly appreciated.  Thanks in advance, Anne   <Well, Anne- I'm thinking that you may have measurable ammonia or nitrite levels in the water...Do check this out, and take appropriate actions (water changes, etc.) to correct.. Regards, Scott F.>

Cryptic Chromis? Hey WWM crew, <Hey there! Scott F. with you!>    I just got my first fish, two green Chromis  to start off my tank. When I got them in the tank, I only saw 1 Chromis all the way at the bottom of the tank by some rock, but he isn't really hidden, and I think he is doing well. But I still haven't seen the other 1. He was the first to enter the tank, so I couldn't see were he went cuz I was worrying about the other.      I still cant find him. I think he might be in some of my rock. Should I be worried. Thanks <Well, I'm taking a guess here. It's hard to know where the missing fish is and why he's hiding. Many times, fishes will hide shortly after introduction to a new tank. They will usually remain hidden until they are comfortable and ready to be out in the open. Alternatively, fishes that are injured, shocked, or otherwise uncomfortable will often seek refuge in the rocks to recover...or die (gulp)...Just needed to fill you in on both possibilities here! I would not be overly concerned unless a week or so goes by without seeing the fishes. Do observe the tank carefully, and monitor water conditions to make sure that everything is A-OK...Keep your fingers crossed, and hopefully, all will be well! Regards, Scott F.>

Chronic Chromis.. >Hi Crew, >>Greetings.  Marina today. >I have a question regarding the behavior of my two blue/green Chromis.  They used to both swim around the tank openly.  After having them for several months, the larger one began chasing the smaller one into hiding anytime he came out.  This went on for several months.   >>Not terribly unusual for certain fish when housed in pairs. >Now for the last couple of months the bigger one has been hiding all the time behind the overflow box with the smaller one.  They both come out to eat but spend the rest of their time hiding. My tank is a 55 gallon and I only have two other fish (Royal Gramma and Pink Skunk Clownfish) neither of which is aggressive toward the Chromis.   >>Actually, I have a good friend in Loma Linda who houses a Maroon clown (talk about a FAT piece of meat that fish is!) and a lawnmower blenny with two green Chromis and they do the exact same thing.  It's my opinion that there is, indeed, aggression in the form of body language that essentially screams to the fish "STAY OUTTA MY WAY!" >The other strange thing I've noticed recently is that as soon as the lights go out at night, the larger Chromis comes out and starts swimming rapidly back and forth along the length of the tank.   >>That is interesting, if it were a horse I'd say that's when he feels comfortable enough to get the exercise/burning off of energy he needs. >This goes on for at least a couple hours until I go to bed.  The rest of the lights in the room are off or very dim.  This behavior must likely be indicative of something but I can't determine what.  I hope that you can give me an idea of what is going on?  I enjoyed watching four fish swim around the tank but it pretty much looks now as if I only have two fish. Thanks for your insight! Bryan Mullennix >>Well, I can't offer much more in the way of insight, nor a way to reverse this state of affairs. But I could possibly offer some solutions.  You're limited with the number of fish you can have in a 55 gallon tank, so consider removing the Chromis and clown, and getting credit on them.  You could easily house a dwarf angel in there (do be selective of species, I'm thinking along C. argi, C. loricula/loriculus lines), sixline wrasse, or fairy/flasher wrasse, very small gobies, such as neon and clown gobies.  All of these would offer movement, though not schooling, and color, withOUT getting too large for the tank.  Marina

The Chromis Were the Culprits? II >Great, thanks. (By the way, I didn't receive a response from you the first time I sent my message, and I value your opinion so much that I couldn't rest until I heard back from you about my concerns, so I resent the message.  Hence the "deja vu".) >>You're very welcome, Barb.  Now I understand, though I'm puzzled that my response didn't come through.. I hope others didn't get lost in electron-ic limbo! >Believe it or not, a week from tomorrow marks the 30 day quarantine point (after my Coral Beauty died) for the Chromis. They're doing well.   Thanks, again.  Barb >>Excellent, I think you, and they, are ready!  Marina

The Chromis Were the Culprits? III >Hi, Marina. (I promise one day to stop pestering you.) >>Hello Barb, it's all in how ya look at it, right? >You made me wise in the past to white, stringy feces as an indicator of an internal infection. If it starts out long, white, and thin and then develops into the orange coloration that I would expect from ingestion of Formula One flake, is that okay, or is it a sign of trouble brewing? >>I would watch them, though the flake can stain the feces.  Just keep an eye, and I *know* you're ready with the q/t! >Two of the 6 blue green Chromis (research revealed to me that, with the absence of a black spot at the base of their pectoral fin, they're blue green Chromis, not green) eliminate in that manner from time to time -- and have for about a week or so. No other problems physically or behaviorally. Call me overcautious, but I just want to be sure I'm bringing only healthy fish into my main tank this weekend. >>Ok, "over-cautious", I would watch them *before* I added them.  At this point, what's a few more days, right?  Sorry I didn't get back to you during or before the weekend, I just haven't been up to snuff the past few days.  Hopefully, either their elimination has improved, or you've kept them in q/t if suspicious. >Also, does one gender of Chromis have longer tail fins? Two of mine have longer forked tails than the other four fish. >>I'm not entirely positive of sexual dimorphism, but it's not uncommon in damsels and other related fishes. >Imagine splitting a piece of yarn in two and twisting each end between your thumb and index finger. The ends look like that. I noticed that tail fin characteristic on my smallest Chromis several weeks ago, but, since nothing else seemed wrong with it, I didn't panic. >>I would tend to think it's either a sign of maturity (possibly sexual) or health. >The second fish displayed it a week or so ago. Could it be a sign of maturity, gender difference, or illness? >>I've never known what we call "trailers" or "streamers" to be a sign of illness.  Quite the opposite. >All other fins look perfect (nothing rotting).  Thanks in advance, once again, my new friend. Barb >>Sounds as though everything's going well (other than the fact I haven't gotten back to you till today), and your fish are likely doing very well if developing streamer extensions on, I'm assuming, the caudal and other unpaired fins.  Glad it's going well.  Marina

The Chromis Were the Culprits? IV >Hope you're feeling better, Marina. We had a bout of the "crud", too. >>Oh my.. mine wasn't exactly "THE" crud, probably a weak bout with a cold more likely.  No fever or sniffles, just a general ill feeling.  All better now, yes? >I took the plunge and transferred the fish from the QT to the main tank on Sunday and everyone seems fine... eating, swimming/playing, and trying to make friends with the other fish (the yellow-tailed blue damsel chases them away from his favorite area, but the yellow tang likes to hang out with them). I think it was the right thing to do... that QT even depressed ME. I'll keep you posted.   Barb >>Please do, what a holiday those little fishes are having NOW!  Hhmm.. do I feel a bout of Christmas prose coming on?  (I grin a devilish grin - here it comes!) -The Chromis Culprits' Christmas- The little Chromis culprits, twice three Set in their new digs Swim about with glee No, not too far From thine Christmas tree (Assuming, I did That you do use A Christmas tree Not Menorah Or other to choose) They frolic and play In their fishy way And swish their fins Splashing this way and that As though to say "Hooray! We're Free! O! Yes, Hooray!"   Yes, cheese it was But the best I can do On the fly Off the cuff As it were Would, could you? Best holiday wishes Barb!  Marina

Man with 125 & 7 Chromis - 6/15/2004 Crew: I know this is unusual, but I am curious about a recent entry in the daily FAQ's.  The person's name was Malcolm Young, and he wrote that he has a 125gal.  Part of his fish stock included 7 Chromis.  I am considering a very similar stocking list, and I was wondering if the Chromis are schooling for him?  I will understand if this isn't something you post, so as not to turn this into a forum, but his stocking list is very close to what I am planning, I thought I would give it a shot.  If this is not proper, can I just ask this; has anyone experienced schooling behavior with any fish in a 125gal, 6 feet long tank?  Thanks, either way, Rich. <Mmm, well, we don't retain others email addys, but I'd bet his Chromis are schooling in this setting... and maybe he'll see your note and write in... Bob Fenner>

Blue School >Cheers! >>Greetings! >Silly question here, I like blue Chromis I have a 150 gallon reef that is just about cycled. It's lit and equipped for SPS (not that that has to much relevance). How many blue Chromis can I add to make a nice top water school? >>This is actually rather touchy, as many normally schooling fish *don't* school in systems with little to threaten them.  I would say, however, a minimum of five.  Don't be surprised if they don't school, though. >Looking for maximum effect but also plan on having other piscine friends.  Thanks, Brian >>Good luck, you would be fine with five to seven in this tank.  Marina

Catching A Cagy Chromis! Good Morning WWM, <Hi there! Scott F. here today!> I just set up a Quarantine tank after a bad case of Ich. I will quarantine all new arrivals. <Awesome! Another quarantine convert!> But my question is: I have only two fish left. A Black and white Percula Clown and a Blue Green Chromis. I was able to catch the Clownfish and put him the hospital tank, but I can not for the life of me catch the Chromis. (he never shows any signs of Ich looks and eats just fine) Is it possible to let the tank go fallow with just one fish in the tank. I don't think I will be able to catch him.  Any suggestions would be greatly appreciated. <Well, you asked...Really, a "fallow" tank means just that- fallow! No fish at all. This is the only way to carry out the process of interrupting the life cycle of the causative protozoa. I'd use any means possible to contain and capture this guy. Often times, fish like Chromis can be more easily captured at night, after the lights are out. You simply shine a flashlight on them, and use whatever fancy netting technique that you've developed to capture them. The only other option is to take advantage of their natural tendency to head into rocks when you try to net 'em. You simply remove the rock that the fish is hiding in, and place it in your treatment tank. Unfortunately, it's easier than it sounds...But definitely worth a try! Good luck! Regards, Scott F.>

Chromis cyanea Hi, I've been a long time reader and of absolutely loved all your articles. Very helpful. I have a question about Chromis cyanea. Will these Chromis school? <Yes... do so in the wild> If so how many would you recommend for a school? They'd be in a 180 gallon. <A small, odd number... 3,5,7... Bob Fenner> Thanks a lot Jeff liechty

- Chromis Behavior - Hi everyone & Bob: <Hello, JasonC here...> Just returned from Hawai'i and had a wonderful time snorkeling in a special reserve along the coast  of Oahu that is protected by the State.  I swam with nearly all the fish that I keep at home in my tank and it was a thrill.  There were literally hundreds of fish in this cove, which is filled with coral reefs.  Can't remember the name but if anyone is interested I'll find out. When I returned I found I have a new problem with one of my three small Chromis.  It swims with the others, but then goes and hides in a cave or under a rock.  It is eating okay.  Isn't this pretty strange behavior for a Chromis?  I was away for two weeks but did a water change just before and 25% when I returned last night.  Tested water today and all parameters are fine.  I think this could be the Chromis who used to sleep apart from the others and who slept with my juvenile clown, who is now teamed up with my larger female.  I have been looking any signs of ill health and can find nothing.  Is he sick or what? <I don't think the fish is sick. Probably just making adjustments to the new space - can take a while sometimes.> Thank you all for all the help you have given me over the past several months.  You have enabled me to have healthy fish, and I sure have learned a lot.  I started with Bob's book but have graduated (but still refer to it) to your website. Hope you all had a great Xmas and have wonderful things happen to you in the coming year. Aloha & Mahalo. Connie Cavan <Cheers, J -- >
- More about the Chromis -
Hi again. <Hello.> This is a p.s. to the note I just sent you.  Could this fish be afraid of my pygmy angel? <That is a possibility.> They used to play sort of a hide and seek game a couple of weeks ago, but maybe it wasn't a game. <Good observation.> Thanks. Connie Cavan <Cheers, J -- >

Large (old) Chromis Damsel Hi There: Just a quick (well probably long before I'm done) question. I currently have 6 green Chromis in my tank. The largest one is about three inches (biggest one I have ever seen ). <Me too!> For the last three days he has been sitting in the bottom corner of the tank (upright not on side). My heat fluctuates anywhere from 76 to 79 degrees throughout the day in the winter. Could that possibly be the reason ??? he looks fine just doesn't move. Is it normal for these fish to do this. ??     Thanks so much.. <Mmm, not normal... may be nothing... not temperature... Do just "wedge themselves in" amongst Acroporid and Pocilloporid stony coral branches in the wild... but might be "old age" catching up with this individual. Bob Fenner>

Rebel Chromis without a clue Gentlemen... >>And women, thank you!  Marina here. Over the weekend I added my first fish into my new 55gal... 4 Blue Green Chromis.  Once in the tank, 1 immediately bolted for a cave, and now 3 days later, he still hasn't come out.  I noticed his head peeking out yesterday morning, and then again last night, but as soon as I got closer he darted back underneath.  Since then there has been no trace of him.  None of them seemed to be sick or anything, and the other 3 are doing great.  >>This is not entirely uncommon. I was told by some friends that it is best to keep the Chromis in odd-numbered groups, but nothing to insinuate that it won't work out with an even number...  >>I know of no hard or fast "rules" concerning odd vs. even number in regards to damsels.  The issue is providing them with enough "buddies" that they don't become further stressed.  Other than that, it's more of an aesthetic issue. I haven't completely given up hope that he will come out, but I'm getting close.  The cave is under a good chunk of live rock that is in the bottom and center of my rockscape, so I definitely don't want to pull everything up... However, I am a little bit concerned that if he never loosens up, I will have a dead fish under there that's not going to come out easy.   Is there anything I can do that may help coax him out?  Should I just keep goin as is and hope for the best?  And if worse comes to worse, how badly will it affect my tank if he kicks the bucket under there? >>I know it's no fun to buy a fish to then never see it again, but he's peeking out.  If he's not feeding, or appears to be injured or otherwise stressed that would be a worry, but you've given no indication that either situation exists.  This particular fish is just not as "self-confident" as the others, and he should soon become hungry enough to want to feed with the others.  Are they feeding well, and are you testing regularly during this cycle period?  One small damsel will cause a bit of a spike in ammonia and nitrites, but a water change or two (or cranking up the skimmer) will suffice.  I don't think that will happen assuming everything else is good.  I think he just needs time to acclimate to his new living situation is all. Thanks in advance for any advice and/or suggestions.  Curtis! >>You're quite welcome, I hope this helps. Marina
Re: Rebel Chromis without a clue
Marina Thanks... unfortunately, the lil guy turned up dead the day after. It looked as tho he had a cut on one side. I never saw anything on him before he went into the tank, so I'm not sure how it happened... possibly scraped himself under the rocks. I'm only guessing, tho. Thankfully, the remaining 3 are doing great. </P> >>Sorry to hear he was indeed injured, but I'm also glad that all the others are doing well. I've been checking the water quality daily all week, and nothing has gone seriously out of whack. I'm going to do a partial water change over the weekend, just the same, tho. I more or less had planned on doing that, anyway. >>Good plan. Thanks for your response and advice. Your website has really been a great resource for me. The wireless laptop, and comfy chair in front of my tank has pretty much all but ended my TV watching habits. Well... at least until y'all get a show on Animal Planet or something.... Thanks again! Curtis!  >>Very glad to have been of help. Marina

Aggressive Chromis Hi Gang, <Hi Glen & Ang, PF here> I yesterday introduced 3 x Blue Chromis into an already established 90 Gallon tank whose current inhabitants are: 2 x Ocellaris Clowns 2 x Fire Gobies 2 x Rainford Gobies 1 x Blue Starfish Just now I closely inspected the inhabitants and found: 1 of the Chromis has a cut on the side of its body about half its width (rather deep) The starfish has a piece eaten out of one of its legs about one third the length of its leg The Firefish' tales are rather tattered. <Hmmm... this all seems strangely familiar...> I straight away put this down to the Chromis' defining who's boss in the tank. <Well, actually, Chromis are pretty mild mannered. My clowns don't put up with them getting near their hammer coral, or me getting near the hammer for that matter.> Should I be looking at removing these fish (my first reaction was to euthanize them, they are very very lucky my beloved clownfish are whole and healthy)? <I'd keep a close watch on the tank and see who the real culprit is.>  Is the starfish likely to live with such a wound (the wound is deep enough that I can see the holes of tentacles from the top of the starfish) and what precautionary measures should I take to ensure its survival. <Make sure it gets it food, and keep the tank conditions pristine. Things should be ok, they have amazing regenerative abilities.>  Have I made a blunder purchasing something remotely like a Damsel which I was advised from internet sources to steer clear of. <Chromis are, as has been said before, pretty mild mannered. Blue/devil/yellow/whatever damsels, OTOH, are nasty buggers.>  Any help you can give would be greatly appreciated, up until now marine fish keeping has been a very enjoyable experience. <They're just trying to make sure you get some excitement, ; ) > Regards Glen & Ang Melbourne, Australia

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