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FAQs about genus Chromis Damsel Stocking/Selection

Related Articles: Chromis Damsels

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

Depends on intra- as well as inter-specific considerations.   Anampses meleagrides.

Final additions to tank      10/18/14
Hi there
Over the past 8-10 months I have gradually added my selected stock to my 500 litre tank. All seems well but just wanted to check my final additions.
I have currently: 3 x Chromis viridis, 1 x Gramma loreto, 2 x Amphiprion percula, 1 x Zebrasoma flavescens, plus one Cleaner Shrimp, one Peppermint shrimp and a tuxedo urchin. From my research I am adding next 1 x Centropyge bispinosus then 2 x Gobiosoma oceanops. However, having researched many places I have found very mixed views on Azure Damsels (C. hemicyanea.) I was thinking of adding 5 of these as my last additions.
<Mixing the two Damsel species might prove too much for the less-sturdy Blues>
They would be smaller than any of my existing stock and I was planning to add last. Whilst never any guarantees, I would value your view given the love them/hate them divisions I have come across
Many thanks Rob
<All the rest are very likely fine... You must be the final arbiter in deciding whether the Azures are worth the risk.
Alternatively I'd consider a small group of Cardinals. Bob Fenner>
Re: Final additions to tank      10/19/14

Many thanks. Would other Chromis be compatible e.g. Orange lined or Blue Reef?
<Easier going species; yes; though I would just stick with one schooling species of Pomacentrid in this size, shape system. BobF>

Hi Bob,

I've had a group of Blue Green Chromis in my system for around 6 months. I have 7 Chromis in total, and all but one seem to be doing fine. I have had them all from young and after a few weeks of having them I noticed that this one slightly smaller fish had either gone 'rogue' or had been kicked out of the main group. The rest of the group now ignore him. They are not overly aggressive towards him, nor is he towards them (I'm saying 'he' but it could be female) but he is definitely not part of the group. It baffles me why this has happened? The only real cause for concern is that he has not grown as much as the other fish. The other Chromis are now about a third bigger than he is. Is this because he is being out-competed for food or is it just that he is a 'runt'? At feeding time he seems to get his fair share and overall I don't think he is in poor health, so the situation feels a little strange. I just feel bad for him!    

John McGuinness

I've heard and read speculations as to 'why' or what species survival value such behavior might confer John'¦ I myself don't actually know the reason, but I have oft observed such 'group excluded' individuals in aquarium and natural settings. Could it be that this is some mechanism for winnowing out less-suitable individuals'¦ as judged by their conspecifics?

          There definitely are crowded situations in captive systems where one or more individuals will be brutalized, perhaps to the extent of their demise, due to insufficient space for limiting damage due to territoriality, but again, I have encountered 'the odd fish out' many times. Most notably perhaps w/ members of the Clownfish subfamily Amphiprionae on and about their symbiotic anemones. Does having this 'reserve' individual serve as a reservoir should the group or pair lose a member? Does the presence of such spares act as a sort of 'whipping boy' promoting agonistic and/or reproductive behaviour. There are numerous examples (some Anabantoids, Cichlids'¦) of such functions in freshwater species of fishes.

            In general I do encourage folks to keep Chromis and other shoaling species in small, odd-numbered groups in captive settings, hoping that the 'odd fish out' syndrome might be alleviated'¦ Such doesn't always occur however.

Fish dynamics. Easily over and mis-stocking a small marine sys. Apogonid f' stkg./sel., Chromis as well      2/10/14
Hi Crew, Just sharing. I have a 24 gallon and usually have six small fish. A year ago I had a Pajama Cardinal about 4 years old, a Clown Goby about 5 years old, a Firefish about 3 years old and a Bicolor Blenny about a year old. So I decided to get a pair of Hi Fin Cardinals and one really dominated the other.
<Yes; not enough room here... but for one Apogonid>
So I sold the dominant one. Then the remaining Hi Fin became bossy and My Pajama Cardinal would not come out and the Firefish rarely came out so I sold  that Hi Fin. The Firefish came out and stayed in the middle most of the day. It took The Pajama Cardinal about 4 weeks to come out and even then it was very skittish. I decided to add an Orange Striped cardinal
 so rather than 2 I decided on 3 and I also went for a Black Axil Chromis.
<Not a good choice here>
 I know it is too crowded but I can always fix that. The Chromis is around the size of the Pajama and is active. The Pajama Cardinal now is out all day protecting his little corner from the Chromis. Didn't expect that. The Firefish is hiding. I think the Blenny unnerves him. The Blenny is moving around much more and doesn't seem to like the fact that there is more competition for him. The Orange Stripes are very small, maybe 3/4 of an inch. But their mouths are very big. They compete for the food and can really eat some big pieces. As of now they look yellow rather than orange. Probably will not be able to keep all three when they are full grown. They stay together near the bottom and don't seem to mind that they are smallest in the tank. When food is there they go to the top besides getting it from the water column. Sam
<Sam; you're a candidate for a much larger system... or systems! I'd be looking about the place; maybe work as well... for location/s. Bob Fenner>

Chromis iomelas - Half-and-half Chromis or Chromis dimidiata...     1/14/13
Hello Crew,
<Hey Paul>
I have been looking for awhile now and I really want to get a small school of either the  Chromis iomelas or Chromis dimidiata-  true Half-and-half Chromis. Can you please help me find this fish... I watch many sites but do not find these and I really would like them.. please help me attain these... or if you could forward this email to someone you know? Please...
<Good question. As you likely are aware, there are some 400 plus species of Pomacentrids, and likely a total of a dozen or so that are "regulars/standards" in the trade (likely to be offered for sale year in/out... The two you mention I have seen many times in the wild, very infrequently in the "system"... as there is little/no demand that makes its way back to the collecting level. I tried an experiment/al urging friend Walt Smith to offer his fave reef damsel (Chrysiptera talboti) and the larger Amblyglyphidodon aureus out of Fiji about 12-15 years back... and these have made some inroads... To respond more substantively, hopefully more helpfully to your query, you're best efforts at acquiring either of these "half and half" damsels is to ask you supplier (LFS if you're a consumer/aquarist) to in turn make formal request of their suppliers...
Quality Marine, Pacific Aqua Farm and SDC (Sea Dwelling Creatures) are my picks (all in LA) for this>
<Bob Fenner, San Diego, CA>
Re: Chromis iomelas - Half-and-half Chromis or Chromis dimidiata   1/14/13

Hello Bob, My last message had my signature link on it.. if you post this message, could you please do me a favor and remove that part of it... I don't want my number and work info listed on your site if that's ok... I forgot to remove it when I sent in my question...
<Ah yes; have left off... does have your location... Do you want this deleted as well? BobF>

Chromis viridis, stkg.      4/22/12
Hello Bob,

<Good Evening Gene, Bobby here>
After the loss of my very large Naso, I've been considering a completely different route and would like your thoughts, please.
As a reminder, my tank is a 125g reef (6' feet) housing:
Yellow tang
6-line wrasse
Flame angel
Clown (1)
(everyone currently gets along just fine and most have been in the tank for over 2 years).
After researching surgeonfish options (all of which get so big as adults)
I'm about ready to move toward a smaller fish and have been considering an odd number of Blue/Green Chromis viridis -- perhaps 5 or 7 -- 3 if you feel I'm overdoing it.
<Although a great reef fish and the numbers you mention will be fine in general, the problem is that over time in the confines of an aquarium this species very rarely will tolerate a group of each other.  It will start with the group alienating the weakest fish and then killing it.  This will go on until only one survives.  I could guess to a number of reasons, but regardless, this is nearly always the result.  If you look at any mature tanks that have housed this species, you will almost always find just one, lone fish.  If you are looking for small fish that will school, consider any number of Cardinal fish.  Do the research first of course.>
Your thoughts, please, on this addition and number to add -- if you agree.
Re: Chromis viridis     4/22/12

Hello Bobby,
Thank you for the informative reply.  Interestingly, as I did my research not a single source provided the details you did.  That's why I like to run things by the WWM team.
<To that point, the info I provided is based off hobbyist experience in the day to day world.  Otherwise, that fish is a great tank candidate> 
It's a shame experiences like you shared with me are not readily available -- or am I just not consulting the right sources?
Thanks for the recommendation on the Cardinals -- they don't really fit my taste so I guess I may be back to finding a suitable surgeon fish.
<If  you are looking for a Tang that is suitable for that size tank, look at the Bristletooth types.  For Example, a Yellow Eye Kole tang. 
Any other recommendations you care to 'run up the flag pole' based on my current community?
<I pair or Trio of Fairy Wrasses might be a nice addition.  Here is a link to the Genus Cirrhilabrus.  Beautiful coloration, sexually dimorphic, and can be kept in a pair, or other combinations of 1 male and more females. 
Although in your size tank a pair is probably good.  Keep in mind, the tank would have to be covered as they can be jumpers, but amazing fish. 

fish needed     2/23/12
Good day,
I was wondering if you could shed some light on a fish for me. The Fish is the Half and Half Chromis (Chromis iomelas).  This fish seems very hard to get.
<Mmm, is collected now and then. Not a great demand for it. Look for suppliers w/ connections in Fiji... Quality Marine, Sea Dwelling Creatures, Pacific Aqua Farms...>
 I am trying a lot of places to find  5 of these guys. Live Aquaria, Divers Den, Blue Zoo, Marine Gardens , Vivid Aquariums and Just Rare Fish but not much luck.
<The first three can get this fish for sure; when it's available... Not hard to catch... shallow water, live in groups that duck into branched stony corals... that can be easily flushed from...>
I really want this fish for me reef tank. Do you have any contacts or Wes Sites were I might be able to get some of these unique fish?
<Again; it's best you just place a "standing order" with a supplier... I'd go w/ Live Aquaria first>
I trust the Wet Web people might be able to at least give me a direction. I have included a photo as sometimes people get the fish mixed up with the more common Chromis with the tail white and ¾ of the body is Black/grey.
<Ah yes; there are at least two other quite-similar appearing damsels; one with an overlapping distribution. Bob Fenner>
Thank you again for any help you might have.

 RMF pic, other lifted

blue/green Chromis. Hlth.. & stkg/sel f'    6/25/11
Hello all, firstly id like to say, Bob Fenner your book the conscientious marine aquarist is amazing, I live in Lincolnshire, England, GB and of all the books I have (which is around 20) yours is the one I come back to time and time again, fantastic, (I wanted to shout that by the way) I enjoy your knowledge and expertise but enjoy tour humor as well. so in a way I have paid you LOL, oh sorry for shouting, LOL.
<Thank you for your enthusiastic acknowledgement Jennie>
I currently have one 45 gallon tank that's been setup for 18 months though I inherited it 6 months ago so never did the cycling, fish stocking etc, (though I did go through a mini cycle when we got the tank, we did keep all the water etc but did do a water change, but the tank came with fishes, live rock, corals etc, as we enjoyed it so much we decided to do are <our> own tank (75 gallons) so 5 weeks ago I set it up with 40 kg of live rock, sand etc, then 14 days ago as the reading read, (and had been for a over a week, I have always tested daily, I enjoy it) ammonia 0, nitrite 0, nitrate 5 (now gone down between 0-1) PH 8.3, copper 0, phosphate 0, SG 1.025, KH 10 (160ish), and calcium 450, all the results have stayed the same and I do test daily, so I brought 5 Chromis, when getting home I had noticed that one of the Chromis had got pop eye in one eye, (the lady that netted them was more interested in going on her break than the wellbeing of the fishes)
<Ahh, a good idea to employ two nets... one for each hand... to herd would-be captures rather than chase them relentlessly; possibly, in this case damage them.>
the fish stayed hiding for 2 days where it then came out one night swam round in circles erratically, then went belly up, I took this as stress, then day three 2 more fish just went in to hiding even though the day before where eating, swimming well etc and then a day later also went belly up, on investigation I had noticed that one had a strange white stuff around its mouth, nothing on the other one, so I'm know left with 2, that was 10 days ago, now my other 2 at the moment doing very well, please note they where the smallest of the group, they feed well, but don't swim together (I'm taking this as there is only 2 and they are babies) they have a wonderful mix of good quality food, and eat all that I give them, (good children) so my question is, did the other fish pass on due to 'breakdown' and stress from netting etc?
<Yes; likely so. This genus of Damsels do "die like proverbial flies" from shipping/transport stress at times>
are my other fish going to make it?
<Seem to be>
(please can you get your crystal ball out for me) and I have a yellow watchman goby waiting in my QT tank and wondered when it will be safe to put him in as he is doing amazingly and been in there for over 3 weeks?
<I would place this Goby w/o hesitation>
(I went to a ten times better LFS, and will never be going back to the other store again, also the other one I've found has my next fishy waiting in there QT tank at the store so I can then further QT him again before he goes is).
look forward to a reply from one of you wonderful people and thank you for such a brilliant website.
From Jennie Bailey
<Thank you, Bob Fenner>

Chromis Stocking Procedure, & Clown comp.  1/7/11
Hi all,
<Hello Paul>
Like so many others, I'd first like to thank you for providing this resource on which I've spent many hours over my 1.5 year involvement in marine aquatics.
I'll be starting up a 72x24x30 system shortly, after having gotten approval from a structural engineer that it won't fall through the floor (split-level townhouse).
The plan is to start with several new Chromis viridis, followed by a transfer of my existing 65 gallon's residents (a 3" Salarias fasciatus, a 3-4" Paracanthurus hepatus, and a 2-3" Neocirrhites armatus -- in
whichever order I can catch them),
<Best to drain the 65 down, move all at once>
and then (after stabilization of parameters and behavior) hopefully a few pairs of clowns. My questions
are these:
1) I only have a 20 gallon QT and am wondering about the best way to add the Chromis. Would something like 2 or 3 subsequent 'rounds' of 4-5 1-1.5" specimens (can the QT even support than many for a month or so?) work?
<This genus, indeed most Damsels period (including Clowns) I am a big fan of not quarantining at all... Better by far to summarily dip/bath and place in the main/display tank. Less stress and much less likelihood of disease actually>
I assume that in a perfect world, they'd all be added together, but I'm hoping the significant space allotted, plus adding each new group just after lights out, plus the general mellowness of the species would allow multiple groups to live together in relative harmony. Can you recommend any alternative strategies?
<Better to place all in one go...>
2) I came across a really cool (and fairly densely stocked) clown tank at the Long Beach Aquarium of the Pacific that I'd like to mimic. Do you think it would be a possible to keep pairs of a few different clown species if I add them in the following order: Amphiprion ocellaris, melanistic Amphiprion ocellaris, Amphiprion perideraion, Amphiprion frenatus, Premnas biaculeatus (or is it foolhardy to house them with other clowns under any circumstances?).
<Almost always so. In large systems... and a six foot tank is considered relatively large, two pairs may learn to live together... Premnas the worst... Ocellaris and Perculas the most agreeable... at opposite ends of the tank>
How many do you think would be able to cohabitate in this 225 gallon without too much aggression (individual personalities notwithstanding)?
<Two pair>
Do you think depriving them of an anemone or corals in which to host would curb territorial aggression?
<Actually, seems to increase in most, more than half by far, cases>
Thanks for your help,
<Thank you for sharing. Bob Fenner>

My Allard clowns seem to have killed my green Chromis, 12/7/10
Hi I have a 55gal salt water tank that has been running for about a yr, a friend of mine moved all its livestock to a larger tank and sold me his 55gal (completely healthy) so I've added about 30lbs of live rock, 10 blue legged hermits, 10 red legged hermits, 10 turbo snails, 2 Allard clowns, a starfish, and 2 green Chromis.
<Chromis should be kept in larger groups, otherwise they tend to do poorly with one dominant Chromis picking off the weaker fish.>
The Allards were added a day prior to the Chromis. Everything was acclimated properly as my friend showed me what to do and he's been running his tanks for almost 2yrs now so I trust him.
<He didn't seem to teach you about quarantine, see here http://www.wetwebmedia.com/quaranti.htm .>
At first all the fish seemed to get along and then bang overnight I find one Chromis dead and floating and half eaten. The other wont leave the bottom of the tank safely hidden amongst some rocks.
<Not a good sign.>
Every time he tries to leave the female Allard chases him back... when he came out of hiding I noticed he had a purplish red spot on his head and side that wasn't there last night.
<These fish will need to be separated.>
Could this be my clowns doing this and what should be done?
<Could very well be the clowns, mixing Pomacentrids can often be problematic. http://www.wetwebmedia.com/damsels.htm .>
Can I ever put more fish into the tank or will they be killed off too?
<You may have particularly aggressive clowns who will not allow others into their territory, or you may be able to add fish from another family that your clowns don't see as a threat. Will have to try and see what happens.>
Please help me.
<For future queries please spell and grammar check before submitting, it saves us time and allows us help more people.>

Just a quick stocking question. 11/14/10
Hey Crew,
I have a 27 gallon aquarium, Which currently houses one orange spotted shrimp goby, two peppermint shrimp , two scarlet hermit crabs and a couple of blue legged hermits. Along with some pulsing xenia and metallic green star polyps. I wanted to add maybe one or two more fish and be completed with my setup. Aside from corals and more live rock to be added later. But back to my question do you think it would be ok to add a Pygmy angelfish (*Centropyge argi) followed by a Sixline wrasse? *
<I do think the Cherub would be a fab addition, but if you go w/ this Pseudocheilinus species (I would not) DO keep an eye on it... this sp. can be VERY picky, as in picking on other livestock, particularly in small volumes such as yours>
*Thanks in advance for any info!*
*you guys are awesome.*
<Thank you. Bob Fenner>
Re: Just a quick stocking question.
Thanks so much for your quick response! On your advice I won't even try the six line wrasse. Do you think 2 or 3 blue green Chromis would be alright or am I borderline overstocking?
<Please read here: http://www.wetwebmedia.com/chromis.htm
and the linked files above. B>
Thanks again,
Re: Just a quick stocking question. 11/14/10
I immediately read your link. Definitely got my answer, I think ill just stick to the angel. Thanks so Much for your input.
<Ah good. B>

Good stocking list?   7/6/10
I have a 30 gallon aquarium (about 36" x 12" x 16") which is fully cycled and water parameters are good. I plan to make it an FOWLR.
Here is my stocking list:
Tank Bred Ocellaris Clownfish x 2
Blue Green Reef Chromis x 3
Would this be good?
<The Chromis won't likely survive in such a small volume for long. There are some other smaller fish groups that have members that would mix with the Ocellaris Clowns though. Please read here:
and the linked files in this series linked above, and embedded where you lead yourself for more ideas.
Bob Fenner>

What Killed The Chromis? Mystery death 5/28/10... env.
Dear sir or Madame,
I have a problem perhaps you can help me with.
<Will try.>
Currently I have a 12 gal. Bowfront acrylic aquarium. It has an i40 model BioWhisper filter. The filter has a mechanical sponge filter and a bio bag cartridge filled with carbon. It cycles up to 40 gallons. I also have a UV
with a powerhead, a protein skimmer, and a sintered airstone (4 inches high) for a bubbler. In the tank currently there is 1 Nerite snail, 1 Cerith snail, 1 Nassarius snail, 1 peppermint shrimp, 1 red Firefish goby, 1 redhead goby, and one blue green reef Chromis (not the larger green Chromis).
I feed them Mysis shrimp and phytoplankton once everyday. Sometimes I will feed them Cyclop-eeze (Instant Ocean gel brand), small amounts of green seaweed or Spirulina alga, freeze-dried brine shrimp, or freshly thawed frozen Mysis shrimp. I add a calcium, magnesium, iodine, strontium, other trace element supplement, vitamin C supplement, Garlic Guard (a supplement with garlic in it), and Selcon (a vitamin supplement) once a week.
<Do you test for all these trace elements, if not I would not be adding.>
Is the gph too much, or too fast?
Is there too many fish in my tank?
The problem is with my Chromis. Originally I had 2 Chromis. But one died just this morning. Before the poor sick Chromis died it was lying on its side and breathing rapidly. It also acted like it had some neurological problems. It was spinning around in circles when it tried to swim. I tried some ammonia and nitrate remover in the tank, to see if that would help the sick Chromis. It did nothing.
<What are your water parameters?>
I saw no detectable injuries on the fish. Its eyes were not cloudy.
Although its eyes were darting about wildly (hence more evidence of some sort of neurological problems).
So then I moved the sick Chromis to a hospital tank. I tried to give it a little Selcon and phytoplankton. In hopes the vitamins and food would help. The sick Chromis was trying to eat at this time, lifting its head up to try and catch food as it went by. But it was not able to get enough in the main tank. I thought perhaps it might have better luck in the hospital tank in regards to obtaining something, anything, to eat. I also gave it a little vitamin C and added a little strontium, calcium, magnesium, and iodine supplement. I did this to help the fish with an nutritional
problems, or lack of iodine problems.
<Again, don't add what you don't test for.>
I was trying everything I could think of because I have no idea what the matter could have been.
The sick Chromis had been acting agitated in the bag when I got it the day before.
<How long did you have this fish?>
The second Chromis seemed fine and was relaxed in its bag. But the sick one was acting very agitated in the bag. The sick one had been swimming up and down rapidly and was darting around, as if trying to escape something.
Well, anyway, I tried everything I could think of to try and save the sick Chromis, but it died a few hours ago. I inspected the poor fish's corpse not long after it expired. I one side of the fish appeared normal. But when I flipped the fish over to look at its other side, I found something peculiar. Just behind its anal fins there was a line of raised scales. I gently lifted back the scales and saw necrotic tissue there. I found this odd because that wound had not been there yesterday. And yesterday the sick Chromis had seemed fine. I did not even see any injuries on the sick
Chromis until after it had died.
<Possibly was there and just missed or the beginnings of post-mortem decay.>
The two Chromis had never shown aggression towards each other. And the Firefish and redhead goby are very peaceful fish. They are not known to attack other fish. And the shrimp and snails are likewise not noted for
aggression towards fish. There are not many very sharp objects in the tank for it to have scraped itself on.
Could the sick Chromis have eaten something that caused an internal intestinal blockage?
<Possible but unlikely.>
Could it have been a parasite?
<Possible but again unlikely.>
I also seem to have a chronic problem with brown algae growing on the acrylic panels in my tank, obscuring everything from view. And my snails are acting lethargic and do not seem to want to come out. And the Firefish,
redhead goby, and shrimp also spend a lot of time hiding.
<Sounds like an environmental issue.>
Should I do a water change?
<When in doubt...>
Should I change the filter cartridge?
<How much live rock do you have?>
Should I cut back on how much I feed the fish at feeding time?
<Might help.>
Is my remaining Chromis in danger?
If so, what do I need to do save it?
<Tough to say without your water parameters, how old the tank is.>
Do I need a bigger tank?
<Absolutely with this stocking level.>
If so, I cannot get one at this time.
<Then return all fish but one, either the Firefish or goby would be best here.>
What can I do to help my tank inhabitants until I can get a bigger tank?
<Lower your stocking levels.>
Thank you for your time, help, and advice. It is most appreciated.
Companion for a Chromis... Not stocking a small SW volume
Hello. I wrote you just recently on another problem I had. I have another question in regards to my remaining Chromis
<This genus, species of Chromis are social animals, live in shoals... can't live in small volumes well or long>
I neglected to ask in my last e-mail.
I currently have a 12 gal tank with a Whisper Bio filter (capable of filtering 40 gph). I also have a protein skimmer, an UV sterilizer with a powerhead, and a 4 in. tall sintered airstone for a bubbler. The current tank inhabitants are 1 Nerite snail, 1 Cerith snail, 1 Nassarius snail, 1 peppermint shrimp, 1 redhead goby, 1 red Firefish, and 1 blue green reef Chromis.
My question is in regards my Chromis. You see, as stated in my last e-mail, my little Chromis lost his companion today. My little Chromis is acting very nervous now. It is swimming rapidly all over the aquarium, almost in a panic. I want to get him another friend to help him feel better. But almost every time I look for blue green Chromis the stores are out of stock, or carry the larger green Chromis, but not the blue green Chromis. I do not want the larger green Chromis. They would grow too large for my little 12 gal. tank.
<... give this fish away, return it to the store>
Are there any other small and very peaceful fish (besides blue green reef Chromis) I could put in the tank with my little Chromis?
I once considered adding a yellow-tailed blue damselfish. I decided against it due to advice from Wet Web Media and facts I discovered later. The facts I latter discovered pointed to a semi-aggressive nature for the yellow-tailed damsel. So that fish species is out of the question for a companion for my Chromis. And I have also tried an orange lined Cardinalfish and a pajama Cardinalfish prior to obtaining my current blue green Chromis. Neither one of these fish did well in my tank. I also tried a yellow clown goby before my Chromis. This did not work out either. The
cardinals and the clown goby all died for some reason.
My redhead goby has been an occupant of my 12 gal. tank from the day it was ready for fish. And the redhead goby is still alive and thriving. My Firefish also seems to be doing fine.
<... what species is this? See WWM re Microdesmids... most live in "pairs", some in shoals... Again, misplaced here>
Except for right now. Right now the Firefish is hiding a lot. I just introduced the blue Chromis two days ago. My Firefish is probably just a little intimidated by the much smaller Chromis still (lol :) ) And I have seen the Firefish out swimming with the tiny little Chromis. So I think the Firefish will get over his fear soon enough. :)
<More likely it will perish, jump out>
I was reading on the Maldives velvet fairy wrasse.
<... no Cirrhilabrus can live in such a volume either>
My sources say it is very peaceful. And it only grows to 3.1 inches (not any larger than what my blue green Chromis is expected to reach). They like to swim in open water. It is recommended they be kept in an 80 gal. tank.
But they did not specify if this was for 1 individual, or a group. Could 1 Maldives wrasse survive in a 12 gal. tank (especially with my other current occupants in the tank)?
And if I just left my Chromis and Firefish to themselves, do you think eventually the presence of the Firefish would be enough to make the Chromis feel better (you know, once the Chromis figures out the Firefish is even more timid than it is)? Or would it still be better to obtain another fish friend for the Chromis?
Thank you for your time.
<I salute your at least "looking before you leap"... and I will tell you that this past year I've been penning a series of articles on stocking small systems... pieces of which are posted on WWM... but the mix you have now, what you have proposed will not work. Bob Fenner>

Green Chromis and Peppermint Shrimp Questions, stkg. sm. SW  -- 04/03/10
I have a 12 gallon saltwater tank. I currently have 1 Nassarius (pardon if the spelling is wrong) snail, 1 yellow clown goby,
<Mmm, Gobiodon really need to be kept w/ live Acropora species>
and 1 redhead goby in the tank. They get fed Cyclop-eeze, Red Tiny Bits fish food, phytoplankton (again pardon if the spelling is wrong here), and Mysis shrimp.
I plan on getting 1 peppermint shrimps (which I read could live in a tank that is a minimum 10 gallons), and 1 green Chromis.
<I'd skip on this last... a social species... that needs more room...>
I know Chromis like to school and they recommend a 30 gal. tank for them.
However, due to the size of my tank, I had little choice but to limit myself to 1.
I chose the green Chromis because they are peaceful, they are apparently not predatory around other fish and invertebrates, and do not grow to be enormous.
<Look into the genus Chrysiptera...>
Questions: Will the Chromis and shrimp be okay in the 12 gallon tank?
(I have a spare 10 gallon tank I can place them in if the 12 gal. tank is an issue.) Will green Chromis eat fish and snails smaller than themselves?
<Not usually>
I am a little worried about this because both my gobies and the snail will only grow 2 inches max. And apparently the Chromis will be 3 to 4 inches max.
<Not here, no>
And will the shrimp eat fish and snails smaller than itself?
<Can... if hungry>
(Same concerns here as with the Chromis.) I hear the green Chromis and peppermint shrimp are fish and invert safe.
<All a matter of degree>
However, they did not specify is this was with all invertebrates and fish, or just fish and snails that are the same size as the Chromis and the shrimp. And also I hear green Chromis can be a little aggressive during breeding time. Being bottom dwellers, would the Chromis leave the gobies, snail, and shrimp alone? Or would they still get picked on by the Chromis?
<See WWM re...>
Thank you for your time.
<Welcome. Bob Fenner>
Green Chromis and Peppermint Shrimp Questions 12 Gal Stocking Keep The Chromis Out...4/3/2010
I have a 12 gallon saltwater tank. I currently have 1 Nassarius (pardon if the spelling is wrong) snail, 1 yellow clown goby, and 1 redhead goby in the tank. They get fed Cyclop-eeze, Red Tiny Bits fish food, phytoplankton (again pardon if the spelling is wrong here), and Mysis shrimp.
I plan on getting 1 peppermint shrimp (which I read could live in a tank that is a minimum 10 gallons), and 1 green Chromis. I know Chromis like to school and they recommend a 30 gal. tank for them. However, due to the size of my tank, I had little choice but to limit myself to 1. I chose the green Chromis because they are peaceful, they are apparently not predatory around other fish and invertebrates, and do not grow to be enormous.
<A 12 gallon tank is completely inappropriate for one Chromis. It will not do well at all in such a small tank. Read here:
http://www.wetwebmedia.com/chromsysfaqs.htm >
Questions: Will the Chromis and shrimp be okay in the 12 gallon tank? (I have a spare 10 gallon tank I can place them in if the 12 gal. tank is an issue.)
<Shrimp should be fine, the Chromis will not.
http://www.wetwebmedia.com/stocking1.htm >
Will green Chromis eat fish and snails smaller than themselves?
I am a little worried about this because both my gobies and the snail will only grow 2 inches max. And apparently the Chromis will be 3 to 4 inches max. And will the shrimp eat fish and snails smaller than itself? (Same concerns here as with the Chromis.) I hear the green Chromis and peppermint shrimp are fish and invert safe. However, they did not specify is this was with all invertebrates and fish, or just fish and snails that are the same size as the Chromis and the shrimp. And also I hear green Chromis can be a little aggressive during breeding time. Being bottom dwellers, would the Chromis leave the gobies, snail, and shrimp alone? Or would they still get picked on by the Chromis?
<Keep the Chromis out of such a small system.>
Thank you for your time.

Chromis (Not for small systems) -- 11/22/09
Hello to whichever lucky WWM crew member gets to answer this email!
<<I guess that's me'¦"lucky" Eric here tonight>>
I've been doing some reading up on Chromis, as I'm making a (small) tank upgrade soon. I will be going from a JBJ 24g to a 34g cube with a 10g sump and an Octopus skimmer rated for 100g. Took a Solana, ripped out the false wall and installed an external overflow.
The plan for the new setup is more real estate, ability for cleaner water and hopefully some success with SPS. Currently I have softies and LPS.
<<Mmm, that's going to be your real problem here'¦in my opinion. Mixing noxious soft corals with 'SPS' in such a small volume of water will indeed make keeping the latter'¦difficult>>
SPS is going to be tough if I can't keep my water quality up, as I absolutely love feeding my fish and LPS.
<<I have a predominantly SPS system and I believe in feeding my fish 'very' well. As stated, I think Allelopathy will be your bigger issue>>
But I don't want to go on too many tangents, let's get to point.
As I'm planning my upgrade I'm looking into the possibility of adding some fish when I make the move. I currently have a pair of Black Ocellaris and a pair of Neon Gobies.
Everybody gets along and is fat and happy... although the Clowns don't like the Gobies trying to clean them at all!
<<I'm sure'¦ These Gobies are better housed in a larger system with more and larger fishes upon which to press their attentions>>
One thing I'm considering is adding a few Chromis - most likely blue-green chromis - to add a little pop and movement.
<<There are better choices than the Damsels'¦again'¦in my opinion
From all my reading thus far I've been unable to find anything hinting at how many can be added to a tank.
<<There's no magic formula'¦ Even identical-sized systems have to be evaluated on their own merit'¦and with these guys, the bigger the better to soften interspecific aggression. Some folks might tell you a 'trio' of the Chromis will do fine in your tank'¦I'm not one of them. In my experience, such a trio will become 'one' in a tank this size>>
Chromis don't seem to need a long distance to run like say a tang,
<<But to group them you need space for 'other reasons'>>
so I would think my cube (19.5"x19.5"x19.5" internal) would be plenty of space for them, and I'm thinking of adding 3 to have a small school.
<<Is a gamble'¦and not a good one I think>>
Any thoughts or advice on this?
<<Indeed, as you've already read. I suggest some research for a trio of a more peaceful species. About the only thing that really comes to mind here for this size system is a smaller and more 'social' Cardinal species like Apogon leptacanthus>>
My other front runner is a Royal Gramma, I've wanted once since I first saw one in person, it would add color, be active, and not be as big of a bio-load as 3 Chromis, but I do fear a bit about their level of aggression.
<<No more so than the Chromis in my experience'¦and indeed a 'better' choice>>
In the same vain a bicolor Pseudochromis or purple pseudo are also on my research list.
<<I would skip on the Bicolor'¦very aggressive to downright mean. The 'Purple' would be somewhat less so, but is still not as good a choice as the Royal Gramma>>
Since it would be the last one in I would think it'd be fine. Appreciate any insight you can give.
<<I hope it makes sense to you/helps'¦ EricR>>

How Many Chromis For A 55? -- 10/20/09
Good morning crew,
<<Evening now'¦Hiya Matt!>>
I have a pretty simple question today.
I have a 55gal tank with live rock that I would like to turn into a reef. The only fish that I want to keep are a school of blue green chromis.
<<Mmm, I see'¦ Your tank may be a bit small for these/this species>>
How many of these fish do you think I will be able to keep in my 55gal tank with no other tankmates.
<<As far as bioload goes, the tank should handle about nine of these fish (given good filtration/husbandry), but It has been my experience that even these 'so-called relatively-peaceful' Damsels will still trouble conspecifics to the point of extermination, leaving one or two individuals in the end, if/when housed in a too-small system. A better choice, in my opinion, would be a small Cardinalfish species. These will do much better, given proper species choice, than the Chromis.
I think this would look great if they were to school around a reef as the only inhabitants.
<<I am much in agreement; but for the 'Chromis' selection. Perhaps Apogon leptacanthus or Sphaeramia nematoptera would appeal to you'¦>>
Thanks for your input.
<<Happy to share'¦ EricR>>

Re: How Many Chromis for a 55? & Apogonid sel. f'  -- 10/21/09
Thanks so much for the advice.
<<My pleasure>>
Apogon leptacanthus actually seems to resemble the chromis in shape somewhat, so if you feel that this would be a better choice then I will try to find them somewhere.
<<Indeed'¦and quite a striking little fish when kept in groups>>
(They seem pretty difficult to find).
<<Do check online sources>>
Now, being that these guys seem to be smaller than the chromis, how many of these would you recommend for my 55gal reef?
<<A dozen should be fine>>
Also, I am really trying to go for the schooling look, so what are my realistic chances with these guys?
<<That depends on your definition of 'schooling look.' If you are expecting them to whip around in a cloud of flashing scales like a school of Sardines under attack then no'¦not these or any other fish available/suitable to the average home aquarium. But'¦ It is my experience that the more social species of Cardinalfishes (of which these are one) will 'hang out in a group''¦though you may want to add a small compatible wrasse species to your tank (e.g., Halichoeres chrysus) for a bit of 'movement'>>
Thanks again!!!
<<Always welcome'¦ EricR>>

Chromis cyaneus, Blue Chromis dying: Chromis Health\Disease Little useful information: 10/1/2009
Hello Crew, I am at my wits end!
<Hi Chris.>
While I have been trying my hardest to search for a viable answer on my own, I have not yet found one. I have not even found one remotely close explanation to my Chromis cyaneus deaths.
I have ordered these fish from three different places, Blue Zoo, Petco and Petsolutions. Every time it's the same thing, fine for about two weeks and they start dropping like flies. I have tried to meth blue them and tried to just leave them alone, still, death. I have had them with fish and alone and poof, gone. I had a set of them in a tank with my fat powder blue tang (which I hear are sensitive fish) and the chromis croak.
<Hmm... how big is this tank? Water testing results? Are you Quarantining?>
I am in fear that they are being poisoned by cyanide, but, hoped that since I got them from three different places, at least one distributer would have some from a cyanide free supplier, or is that visa versa?
<Blue Chromis are tropical west Atlantic\Caribbean fish, cyanide poisoning is unlikely.>
Is there any info as to why they croak? I heard they were supposed to be a fairly hardy fish?
<They generally are.>
I also keep hearing the coined words 'don't ship very well''¦..really?
<Depends on the method of shipping\etc>
I am trying one more batch which I should be getting in no later than Friday. I am going to try to get some real ocean water form the store and put them in that.
<That should not make a difference assuming the water quality in your tank is good.>
I am also going to assume they will not be eating for at least a few days, so, as soon as I get them in, what should I do with them?
<Normal dip\quarantine procedures.: http://www.wetwebmedia.com/quaranti.htm and http://www.wetwebmedia.com/dips_baths.htm >
Should I skip the meth blue dips?
<I would not.>
Is/are there any vitamins I can add to their tank water? Any other tips? Preferable salinity, temp, classical/rock music for this variety?
<Normal sea water - pH 8.2 - 8.4, salinity of 1.023 - 1.025, no ammonia, nitrite, and nitrate less than 20ppm>
What can I do to make sure they survive?
<Have a read here: http://www.wetwebmedia.com/chromis.htm >
Thank you so much in advance, Chris

Question About Genus Chromis of Different Species, sel., beh.    1/10/09 Hello, <Wes> I've recently set up my new tank and am looking for the last couple of fish to add to it. I have two Chromis virdis currently and would like to add a couple more fish from the same genus, but, perhaps a different species so that there will be some more color to the tank. Related to that, I have a few questions: <How large is this tank? Shape?> 1) Will Chromis from different species school together or is it best to stick to just one species? <Some species do associate in the wild and in captivity, particularly with C. viridis> 2) I've read that Chromis cyanea are difficult to keep and that they get mean when they get older. <Mmm, these are relative terms/measures... I rate C. cyanea pretty low relatively on being difficult to keep and mean... amongst Damsels, marine fishes period... maybe they'd get a 3 or so on a scale of 10 IME> I've found Chromis insolata and Chromis limbaughi to be listed as peaceful and easy-to-care for fish, but wanted to see if you have any further input on these different species. <Have seen and kept both of these... and they are actually slightly both higher on the improvised scale mentioned above... and not great schoolers to boot> As always, thanks in advance for all you folks do! Wes <Again... I do wish you had mentioned the size, shape of this system, the other livestock, perhaps the gear... I might look to other families of fishes period to mix with the present Chromis... perhaps Anthiines, Apogonids... Bob Fenner> 

Re: Question About Genus Chromis of Different Species 01/10/09 Hi Bob, <Hello again Wes> Sorry - I forgot the most basic of information! I downsized from a 125G and so had to make some great cuts. The current tank is a 60G at 48" long with a 40 gallon sump. Basic equipment is a 1100 GPH return pump, two powerheads, phos reactor and a skimmer rated for a 150. <Ahh, this system is too small volume-wise to accommodate a "school" of damsels of any species> Current livestock are one each of Ctenochaetus tominiensis, Zebrasoma flavescens (I recognize it will likely outgrow the tank and have to be moved out; however, is a leftover from the 125), Amphiprion ocellaris, Halichoeres melanurus, Gramma loreto and the two C virdis. It is a reef system with a lot of softies and a few LPS. Based on this stocking, I think I might have room for two, maybe three fish that would stay relatively small but be pugnacious enough to compete for food. The tank looks good now, not busy, each fish with plenty of room to swim and lots of hiding places, so want to keep that appearance. <I would not add any more fishes here period> Ideally I would like to add some blue to the tank which was the thought behind the C. cyanea; however, if there is a more suitable fish, I'm open to ideas! Thanks again, Wes <I wouldn't place more Pomacentrids, even of the same species present here... Too likely to be social/territorial issues all the way around... for this amount and shape of water you're "all filled up" fish-wise. BobF>

Chromis aggressive - 07/19/08 We have four green chromis and two purple (look black) Chromis. We've had them all for over six months, no problems with them or with the other fish. All of a sudden one black chromis is continually chasing the other black one, they were both added to the tank at the same time when they were small. Is this an indication they might be wanting to breed, or?? One has the other hiding to get away from it. Marilee <Mmm, though, amongst Damselfish genera, species, Chromis tend to be "more mellow", there are individuals who are at times quite aggressive... Particularly when kept in too small settings, in too small groups... I'd likely trade in the more agonistic one here... unless you have room, desire to add several companions. Bob Fenner>

Blue Green Chromis, sel., sys.   3/10/08 Hello Crew!!!!! Okay, here it goes. I have a 55 gallon reef tank with some mushrooms, leather, zoos, and polyps. Currently I have 10 Cerith snails, 5 Astrea snails, 2 tank raised common clowns, and a lawnmower blenny. Also have about 70-75 lbs of live rock. Readings are as follows: pH = 8.4, Nitrates = 5-10 ppm, Nitrites = 0, Ammonia = 0 <<All looks fine>> My question is............I REALLY want a school of blue green chromis. I was thinking 5 or 7. If this is all I put in my tank (other than what I already have), do you think it is possible? If not how many, and if none, what else would you suggest? <<Due to tank current stocking and size, 5 is the maximum i would go for...On that note though, i have always felt that Chromis do school better in numbers larger than 5... Don't know if that will influence your decision..>> <<Other suggestions would be goby's, blenny's, Firefish>> Thanks for all of your time and hard work. This site has helped me learn more than you could ever imagine about saltwater and reef keeping. Thanks again. Matt <<Thanks for the question. A Nixon>>

Stocking question: Chromis in a 36G  3/2/08 Hello, <Ron> I have a stocking question on my system.? It is a 36 gallon aquarium (Tunze Nano skimmer, Emperor 280) that has been up and running for 8 months with the original inhabitants (1 small red legged hermit, 1 True Percula Clown), a few Nassarius snails and a Camel shrimp.? I have converted over from the original crushed coral to a shallow aragonite sand substrate and am switching over from the original red lava rocks to some Marco rock dead rock and will add live rock in the near future. I have recently acquired a small QT tank (12 gallon Eclipse) that has just finished cycling using a frozen shrimp. Looking for a new addition to be a peaceful, colorful and active addition.? I was considering a pair of Blue/Green Chromis as I like its attributes, but then began reading.? I believe three is too many for a 36G system, two is not preferred as odd numbers seem better to divide up any aggressions and a single one does not seem the best either for they prefer to be in numbers. <Is really too small period> Which of these (1,2,3) is the least of the evils, or would I be better off passing on the Chromis and going with another route?? Overall I will look for 3-4 fish total for the system, and would like all to be reef compatible should I eventually add a coral in there. <Mmm, depends on the species... I would avoid C. viridis et al. large number in schools types... Perhaps some more solitary Chrysiptera genus would be better...> Some others I am considering are: Royal Gramma, Firefish Goby, Fridmani Pseudochromis (although these seem pricey). <Please read re on WWM...> I would appreciate any suggestions you could make to the Chromis plan or another peaceful/lively combination. Thanks, Ron??? <Enjoy the research. Bob Fenner>

Purple Chromis  -02/20/08 Good evening crew, I was wondering if you guys know anything about Purple Chromis, Chromis scotti? <<Chromis scotti is correct>> The pictures I've seen of them are beautiful, but I can't find any good information on them. <<Basic info for you here then...A nice peaceful fish, very much the same as the normal chromis. Grow to about 4 inches, feed on meaty foods, frozen preparations and foods of that ilk. Adding good vits to the foods. As with other Chromis, best kept in a school, but can be housed as a single>> Would one of them do well in my twenty-nine gallon reef tank? <<Yes, you could keep one in your tank>> Thanks in advance, Brandon <<Thanks for the questions. A Nixon>>

Green Chromis -- 1/26/08 Hello, In my tank I have a school of Green Chromis. I want to add some more, but I heard that the existing fish in the tank will fight and kill the newcomers. Is this true? <Mmm, a possibility... given enough room though... not necessarily> Is there anyhow I can avoid this problem? <Ways you can reduce the likelihood... Rear in a "parallel" system, moving some water back and forth weekly... till the new specimens are large/r, healthy... move all over to the one display during the "just dark" period of the night...> I don't want to wait for all of the existing chromis to die before I add more fish. Thanks for your time, Aly <Please make your progress here known. Bob Fenner>

Urgent marine advice needed. so many mistakes, so little time... Chromis... -- 09/08/07 Hi guys/gals, I've been up all night reading through your FAQs, and I've got myself in an awful tizzy. Apologies in advance for the very long email, but I want to make sure you've got as much info as possible Background (please don't yell at me): My partner and I started last October with a 60L tank (15Gal), FOWLR (+ Hitchhikers - crabs, pistol shrimp). Our only fish was a Valentini Puffer (Puffy- yeah, i know, original!)- <Needs more room... Oh, I see this directly below> we shortly realised that the tank was too small for her, but have only now been able to upgrade. The tank was also getting an anemone infestation due to Puffy's messy eating and inadequate filtration. So, start of August, we bought a 220L (55Gal) Cube (AquaOne brand), and intended to use our 60L as a quarantine. <Better...> The tank has crushed coral sand and a Jaubert cavity, and the filter/ sump is an AquaOne Marisys. We have about 23kg (~50 pounds) live rock, which was bought in 2 halves, a week apart. It had been cured at the store, looked and smelled healthy. Puffy was moved over within a couple of days of the 2nd set of rock being added. Ph was 8.3-8.4, Ammonia and nitrite were 0 and nitrate was 10ppm at the time. <Good...> The following weekend (mid august), I was away, and my partner purchased 3 hermit crabs, and a cowry. <Mmm, food> (Puffy has never shown the slightest interest in the crabs in her old tank, and is an incredibly good natured fish). The following day, he purchased 4 blue/green Chromis, which had been co-habiting a tank with another, larger, valentini. The idea here was to acclimate Puffy to the presence of other fish, as she'd been so long without company. He put the Chromis directly into the main tank, as the quarantine tank had not been set up (still had the old live rock in it). So, the Problem(s): After putting the Chromis in the tank, 2 developed bruising. <Likely, oh, I see this below as well> We figured that this might have been to do with their violent reaction to being netted, but thought we should do our best to quarantine them anyway. So the quarantine tank was prepared (or so we though), and the Chromis were once again caught, and transferred. A couple of days later, and after some evidence of bullying, one of the Chromis with the bruising started to develop rapid breathing and stopped eating. We checked the water and there was 1.0ppm Ammonia. we did a water change (mixing our own from tap water... yes, i know now...), and it didn't help. Eventually we checked the tap water and to our horror found that it already had ammonia in it. We freaked, read all about chloramine, and went back to our LFS to pick up some sea water. But we also moved the Chromis back into the main tank (we'd had them for a week by this stage), thinking that it would be better to get them out of the ammonia. The fish exhibiting breathing problems lasted another couple of days, but then we found him dead one night. The other fish (including the other bruised one) seemed fine. When we extracted the dead fish, I examined the body, and it did indeed seem that the bruise was in the same area as some missing scales (and therefore probably caused by netting trauma). That was about a week and a half ago. A couple of days ago though, another of the Chromis started showing breathing problems, was hiding behind the rocks, and wouldn't eat. He was also being bullied a bit by the other two, (who regularly have their dorsal fins raised, and seem also to be butting tails with each other a lot). Water parameters were 8.3ph, 0ammonia, 0nitrite, 15nitrate. We found him dead this morning. I couldn't see anything particularly wrong with him (there were a couple of darker scales, but they were fairly consistent with night time colouring). So, I've been reading through your chromdisfaqs page and came across a disturbing possibility that this is Velvet (see 3rd from bottom). I haven't noticed any of the fuzziness associated with it though. <Is not Velvet... I assure you... if so, all your fishes would be dead> The other 2 Chromis are fine... so far, but then again the 2nd one only started having problems after the 1st one had gone. Solution?: As horrible as it sounds, my main concern is Puffy (obviously I don't want the remaining 2 Chromis to die either, but if it comes down to the choice... ). The only thing is, I don't know what to do about it. I thought about moving her to the QT, but if it is velvet, then presumably our QT is also infected from the week that the Chromis spent in there (I assume it would also be in all the filter material, so to clean it out we'd essentially have to start with a completely un-cycled tank (new water, new filter material, no live rock/ substrate)). I also don't want to risk treating the QT with copper with her in there (I've read on WWM that it can be done with puffers, but that it's risky), but due to the speedy nature of the problem, would want to act ASAP... Also, if it's not velvet, and is just bullying, then we'd be putting her through unnecessary stress, and back into a small tank that we don't have any good way of keeping good water quality in without any liverock... Please help! (I don't know if you normally reply by email, or just post onto the site, but if possible, could you please reply by email so I know as soon as you've replied?) Thanks so much -Jo <We do respond to all directly... I fully suspect as you state that the larger part of the source of mortality with these damsels is/was trauma... before you received them. Some batches of Chromis do "just die" easily... likely resultant from the vagaries of collection, holding, shipping... and your system is very new... and not really large or a good-shape for these Damsels... I would NOT treat the tank... Nor really add any more Chromis spp. Do wait a couple of weeks... and re-formulate a stocking plan, chat with your stockists... Cheers. Bob Fenner>

Sending Chromis To School (Schooling Size) -- 07/18/07 Hello, <Hey there! Scott F. back with you tonight!> I have a cycling 86g tank that I plan on stocking with a pair of Maroon Clowns, snails, a BTA, and Chlorodesmis fastigiata. <Sounds nice!> I'm currently looking at schooling fish and have my sights on Chromis acares, Chromis viridis, and Chromis vanderbilti. I'm trying to create a biotope aquarium, so I want to know how small their schools/groups/shoals can become in the wild, i.e. is it common for them to swim in groups of 5 or 6? Thanks in advance, Random Aquarist <Well, Random- I'm looking forward to seeing this biotope come to fruition for you! Chromis are usually found in shoals, sometimes numbering hundreds of individuals. You can certainly keep them in small groups of 5 or 6 in captivity. However, in captivity (as in the wild), dominance hierarchies may develop, with the subordinate members bearing the brunt of the dominant fishes' aggressions. Often, aquarists will start out with a number of individuals, and the population will dwindle to a couple, or even one fish. I've seen the best successes with Chromis atripectoralis (The "Green Chromis"). It's not the nicest of the bunch, but it is a beautiful fish in its own right. It does reach a larger size (like 3-1/2" to 4") than some of the other members of the genus, but it seems to do better in groups. I've seen a large (180 gallon) reef system with a shoal of 12 or so of these fishes, and it was beautiful. The aquarist had made many attempts with other species, yet finally achieved lasting success with this species-the shoal is still going strong after 3 years! Do consider this species and see if it works for you. And please keep us posted on your progress with this system! Go biotopic! Regards, Scott F.>

Atlantic Blue Chromis (Chromis cyanea)  4/14/07 Wet Web Media - <Mmm, is this the person who was chatting with Morgan Lidster... (Inland Aquatics)... He and I talked on the phone yesterday re this species...> I have a question concerning the mortality rates of the Atlantic Blue Chromis.  I have designed and setup a 90 gallon reef tank as a niche biotope to the Northern Gulf of Mexico. <Neat> The tank was setup a year ago and invert and sponge growth has been great.  The rockscape will feature large boulder type layouts and will feature 3 Pacific Montastrea corals, a couple of Porites and a lone Gorgonia.  One of the Montastrea's is farmed and I was able to acquire 11 frags from the same mother colony to simulate one coral dominating the area, with the others scattered in to give some color and texture.  Other inverts would be the Orange White Claw Hermit (C. tibecins?), Coral Banded Shrimp pair and a dozen Cerith snails (they should breed to a stable population up or down depending on the algae available). The fish plan was to feature a pair of neon gobies and a school of 7 blue chromis (C. cyanea).  All my research on the web and in books indicates everything should be okay and my biggest problem will be that they may not school once comfortable in captivity, <Perhaps in time...> not a concern to me.  However, in looking for a source to purchase these fish, I am finding that they are in fact difficult to keep. <Mmm, yes... I think this is mainly due to the fact that this fish is poorly handled post capture/collecting... but it also does not adapt easily to captive conditions>   This is the first I have heard of this and I see no references to this, not even on this site. <Mmm: http://www.google.com/custom?domains=www.WetWebMedia.com&q=chromis+cyanea&sitesearch=
3A000000%3BGFNT%3A0000FF%3BGIMP%3A0000FF%3BFORID%3A1%3B&hl=en> What are the issues with keeping these fish? <This fish? As stated above... it doesn't "like" being netted... like Zanclus, Dascyllus albisella, a bunch of other examples... it seems to die easily from "stress"...> The tank is pretty much dedicated so it would not be much effort for me to meet any known special requirements.  Is there anything special I need to do?  Is my fish stocking plan destined to fail? <Mmm, not necessarily... I think you have better chance than most all folks here... with your biotope of size, age... Just need to find someone willing to ship you the Damsels. I'd try contacting some of the "diver-direct" sources in Florida...> If I need to change my fish stoking list, can you recommend another fish in the Gulf that would do well with my plan (perhaps the Purple   Reeffish)? Thanks, Chris Sanchez New Orleans <Mmm, well, there are always "standard" animals from here like the Pearly Jawfish... But do try the Chromis... Bob Fenner>

Re: Atlantic Blue Chromis (Chromis cyanea)   4/16/07 Bob Fenner, thanks for your reply.  Being that there are no other fish in my aquarium, would you still recommend quarantine? <With this species, situation, no>   My concern is that quarantine will cause additional stress that may lead to a higher likelihood of mortalities since QT tanks are seldom as large and as mature as the display tank. <We are in agreement here>   For example, I use a 3 gallon for coral quarantine with no skimmer or live rock and perform daily water changes.  A school of chromis would not do well here so I would need to start over on the QT setup.  What would you recommend as the minimum quarantine standards if I were to get the Chromis five at a time? <I would still directly place this number, species, in the ninety posited, w/o quarantine... in batches> Tank size, equipment, rock/substrate, aged (1 month, 3 months...)?   Thanks Again. Chris Sanchez New Orleans <Welcome. Bob Fenner>

How many chromis? Damsel Ident.... Dasc. re-send... 7/4/7 Hi Lisa, stocking question for you. <<Hey Elise!!>> My current set up is a 130 gallon FOWLER with a wet/dry trickling over bio-balls (supposed to be a nitrate factory, right? I am not experiencing this). <<Not always. It may with time.  Water changes/macro algae can curb this.  Do keep on top of maintenance.>> It has a built-in skimmer, which I have "tweaked" a bit to improve performance. I have 75 pounds of live rock, turning nice and purple. The set-up is about a year old. Inhabitants are a four-inch blue tang (Dori, my pride and joy), a tank-raised perc clown, a juvenile sailfin tang, one yellow tailed damsel, two three-striped damsels, two other brown damsels of unknown species, a Banggai cardinal, <<I prefer these are kept in groups.>> a golden-scalped goby, two skunk shrimp, some hermit crabs, and two green chromis.  There is some minor bickering, but no one is getting picked on too much, so far.  (I know, I need to watch the damsels as they get older). <<Do not underestimate how nasty some can get.>> I have read that the chromis look really spectacular kept in a school.  I'm thinking about getting several more, and I'm wondering, how many could I get, assuming it's not a terrible idea? <<Not at all.  I prefer them in groups of at least 7 if you have the room. I do worry about the number of damsels you have in your tank (clowns and chromis are dams too!).  If you can remove any of the damsels (not clown and chromis), I would.  Add a few more Banggais (tank bred only please) and 5 or more chromis.>> I plan to not add any more inhabitants after this. I'm attaching a picture of the brown damsel, wondering if you can identify. (I apologize if it's too big, I don't know how to re-size and the computer genius is out of town!) I've been searching, but I can't find him. <<hmm, I can't seem to see it.  Do take a look here: http://www.wetwebmedia.com/damselidfaqs.htm, http://www.wetwebmedia.com/damsels.htm .>>   Thanks, I'm still really enjoying the site, I peruse the FAQs every day. <<Me too!  Glad to help my friend. Lisa Brown.>> Elise

Stocking Opinion   3/31/07 Hi Crew, <Jason> Thank you for all your effort in providing this forum.  My tank is pretty much all stocked up, but I am considering whether or not to add another fish (tang) or small school of Chromis (four) to the tank.  I apologize if this is too much information, <No such thing> but here is what I've got: This tank was up for 14 months before I tore it down and started again due to a massive green hair algae problem.  I think this was brought on by my lack of a chiller last summer and temperature spikes into the mid-eighties.  Current set up running for seven months and appears stable, but I remain paranoid about algae & bioload. 200+ gallon custom "show" configuration - 54" x 24" x 40" (tall), <Wow! Hope you've got basketball player-length arms!> maybe 240 g total volume w/ sump less rock. 2 x 250 MH lighting (10.5 hours/day/offset a bit) + 90W actinic (14 hours/day) Several hundred pounds of live rock, & 4" live DSB Sump filtration w/ sock, protein skimmer, activated carbon, UV sterilizer Four water returns w/wave-maker and 3000 gph pump - nice variable flow. Automatic water top off system and bi-weekly water changes between 10-25% A chiller.  Water temp quite stable @ 79F. Calcium reactor on order. No refugium as there is simply nowhere to put it. I can't figure out how to add macro-algae to the sump w/o fouling the pump. <Screening, partitioning likely... to have water spill over... leave the algae behind... or divert main flow around the algal culture area...> Water parameters checked weekly.  Calcium a bit high at 500ppm <Yes...> (Salifert), Alk ~ 11. pH 8.1-8.2, Nitrates/Nitrites = 0 I have numerous soft corals: Two sizable toadstools Large, growing leather coral Purple frilly (I think) gorgonian- 18" tall Five zoanthid colonies. One frogspawn, one purple xenia Two green polyp colonies. Two other soft colonies I can't identify. 3 LPS colonies I can't identify 5 SPS (acropora) frags.  I started these about two months ago, and they are mounted at water depths less then 12", four of them within 6" of surface.  They seem to be growing well and I've constructed a coral skeleton high in the tank to mount some more if all goes well.  For now, I am waiting on Anthony Calfo's book on coral propagation before spending any more money. <A good investment> The fish: 1 yellow tang - 4" long 1 hippo tang - 2.5" 1 pair false percula clowns - 2"-3" 1 pair longnose hawkish - 3" 1 pair (male/female) watchman gobies- 3"-4" 1 six line wrasse (2") 1 unknown wrasse - 4" long (primarily purple body, wide yellow horizontal stripe down each side, blue tail) 1 orchid Dottyback - 2" 1 pair cleaner shrimp 10 blue leg hermits 10 scarlet hermits 1 sally lightfoot crab. (The one with the yellow bands on its legs, not the one identified as sally lightfoot on WWM crab page.) 6 turbo snails, many Astrea 1 narcissus snail & two sand sifter stars.  (I think you disapprove of these but I got tired of cleaning the brown scum off my sand and these guys keep it pretty clean but not spotless, so they are hopefully not starving.) <Likely fine here> I have to admit, the fish are happy as is, so I am reticent to add.  The only problem is the male goby does not like the female, but I think there is enough room for them to avoid each other. <Okay> I feed 1 cube frozen mysis daily, sometimes 2 cubes.  Also feed a playing card worth of Nori most days, as in my experience the tangs starve without it and all the fish enjoy it except the Hawkfish.  (I should emphasize my experience with this.  I had ridiculous amounts of every kind of unwanted algae and my tangs still went skinny.  After I began feeding the Nori sheets in a clip, they remained healthier and pick more algae off the rocks.) <Thank you for this> I also use a light dose of plankton or DT oyster eggs most days with skimmer off for 3 hours, primarily for the corals. (Also a drop of Lugol a day in the sump, although not exactly "food"). So...hopefully that is all the info you could ever want to offer an informed opinion. Would you recommend that I refrain from adding either an Atlantic Blue Tang (an Acanthurus in addition to my Paracanthurus and Zebrasoma) OR four green or blue Chromis to this party?   <Mmm, all should go fine... I would make the Chromis number odd... 3 or 5 let's say... tend to stay in a school more...> Separately, should I be concerned about too many corals as it relates to bio-load? <Mmm, no... but do want to mention that if you were going to add more, you should do so... soon, and otherwise let what you have "grow up" by itself> Thank you so much for this and all your other efforts.  For what its worth, I've bought two books by Anthony/Bob as a testament to the value of your knowledge. Jason <Well okay! Thanks for writing/sharing. Bob Fenner>  

How many chromis?   3/31/07 Hello fish gurus,  I sent this a couple of days ago and haven't received a reply, <Mmm... haven't seen...> I attached a pic that I'm afraid was too big, so I have resized and I'm trying again. (sorry, hope I didn't crash your server). <If so, we'd tell you...> I have a stocking question for you.  My current set up is a 130 gallon FOWLR with a wet/dry trickling over bio-balls (supposed to be a nitrate factory, right? <Can be> I am not experiencing this, at least not yet).  It has a built-in skimmer, which I have "tweaked" a bit to improve performance. <Good> I have 75 pounds of live rock, turning nice and purple. The set-up is about a year old. Inhabitants are a four-inch blue tang (Dori, my pride and joy), a tank-raised perc clown, a juvenile sailfin tang, one yellow tailed damsel, two three-striped damsels, two other brown damsels of unknown species, a Banggai cardinal, a golden-scalped goby, two skunk shrimp, some hermit crabs, and two green chromis.  There is some minor bickering, but no one is getting picked on too much, so far.  (I know, I need to watch the damsels as they get older). I have read that the chromis look really spectacular kept in a school.  I'm thinking about getting several more, and I'm wondering, how many could I get, assuming it's not a terrible idea?  I plan to not add any more inhabitants after this.   <Mmm... I think it's a good idea to add more!> I am attaching a pic of the brown damsel, hoping you can identify it. <Mmm, the pic attached has a Dascyllus... but this is not a brown animal...?> I've searched, but I can't find it. It was an impulse buy.  I am afraid you are going to write back and say its species is "demon-from-the-netherworld" or something like that. They've grown a lot already, and they are aggressive little boogers, but the balance of power is intact, so far. <And in a system of this size, configuration, likely will continue... There are some very "bad" members of this genus: http://wetwebmedia.com/dascyllu.htm> Thanks again for all you do here.  I love reading the daily FAQ's, it's all so interesting. Elise <I would go forward with your plans for adding more Chromis... perhaps another five or seven individuals. Bob Fenner>

Re: How many chromis?   3/31/07 Ah, Mr. Fenner!  Shouldn't you be diving rather than answering emails? <Heeeee! Of course you're right....!> We will be in Hawaii in early June, our fourth trip to Kauai, and first to the Big Island. I can't wait to commune with my fish buddies (i.e. snorkel)!  Thank you again so much for your time and invaluable advice.  Here's a small pic of my system (Dori stopped to pose) Elise
<Thank you Elise. Bob Fenner>

Stocking question... sort of like Seuss... One fish, two fish... wanting blue fish, Chromis   3/30/07 Hello WWM crew, love your site! <Thank you> I have been keeping freshwater fish for 35 years and switched over to saltwater 6 months ago and almost feel like a rookie again, as well as a child at Christmas. <It is indeed exciting> My current system is 110 gal with 110 lbs of live rock and 40 lbs of aragonite sand, 2 Seio 1500 ph, a/c 110 power filter with charcoal, which I change every 3 weeks, and a Remora Pro skimmer. I do a 12 gallon water change every 2 weeks with RO water. My current fish are 1 Kole tang, 1 Flame Angel, 2 False Clowns, 2 Firefish Gobies, a Royal Gramma, a Filamented Flasher Wrasse, 1 Tricolour Anthias <Would do better with companions> a Yellow Watchman Goby, 3 green Chromis', 3 blue leg hermit crabs, 2 Cleaner Shrimp, 2 Peppermint Shrimp, 9 various snails and about 7 soft corals. My water parameters are good although the nitrates stay between 10 and 15. My wife and I think we need some blue and were thinking of adding 2 blue reef chromis, my LFS says no problem but I am not sure. What would the experts recommend? <Well I don't think they would be a problem in terms of bio load. However they are shoaling fish and although they may join the 3 existing chromis they might look a little out of place, personally I think you're stocking list sounds very nice at the moment. But technically you should be ok with these additions> Thanks and keep up your much appreciated site.  Keith <Thank you for your appreciation and good look with your endeavours, Olly>

Chromis Stocking advice. (Number; When) 2/18/07 Hi Crew, <Hi Jason, GrahamT here.> Thanks for your great advice in the past. <Glad to be of service to the community!> Now I have a request for simple stocking advice. I have a 90g reef tank (plus 30g sump/fuge) with ~120lb LR total. My current livestock includes:   two black&white Ocellaris (max 2" long) <You mean now, not eventually, right?>   one bicolor blenny (about 2.5" long)   one purple Pseudochromis (about 1")   one candy hogfish (Bodianus bimaculatus) ~4" [this guy can be a little aggressive towards the other fish] <He *is* a full-grown adult, though usually a docile tank-mate. Goes to show you, personality can be a factor in any selection you make.> I also have many soft coral, and a few large-polyped stony corals, and zoanthids/Palythoa. <Sounds fun!> I'd like to add a school of Chromis to the tank as my final set of fishes. <May have been better to add before the Hogfish, and probably the Pseudochromis, as well.> Given my setup, how many do you think it wise to add, if any? <In that system-size/bioload, I would normally say 3, with no more than 5 individuals.> Which species is best for schooling while minimizing size and care requirements? <These are a favorite for both reasons. Also, Nemateleotris magnifica and Ptereleotris zebra are also notorious "groupers." > Will my hogfish terrorize them incessantly (it continually chases the Blenny until the Blenny ducks into a hole). <If he's spunky, he just might. Then again, he *shouldn't* perceive them as a threat, and they will likely defer to his/her superiority. Sometime when you look at blennies, they just seem to be saying, "So what?!? What are YOU gonna do about it?" and you can understand a hogfish's inability to cope... ;) If your corals aren't too established, and/or you can accomplish it without too much destruction, you can always re-decorate to throw off the territories.> Thanks for advice! Jason <You're welcome, Jason -GrahamT>

Re: Chromis stocking advice 3/28/07   4/2/07 Thanks for the advice, Graham! <Welcome, thanks for writing in.> In response to our last conversation... do you really think 5 is the upper bound on these? <Well, within reason, you might add more, but they do grow large enough that their adult size would have them crowded at more than 5 or so.> These are the last fishes I plan to buy for quite a while (if ever) for this tank, though more coral possible. My total volume with sump/fuge is ~120gal. I was initially thinking 9 chromis fish all introduced together. Overkill? <It's your system. You might be able to make this work with the proper care and practices.> Also, I never got the last response e-mailed to me (just saw it posted on FAQ). Guess it was a bug. <Oh, yes. We have those.> Thanks! Jason <Welcome again! -GrahamT>

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.>

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.>

Blue Reef Chromis in Nano..- 5/9/2006 Quick question - can I keep a single blue reef chromis? <<I wouldn't, no.>> If not, can you suggest a good BLUE fish for a nano?  I have a pair of [very] juvenile (1") ocellaris clowns and a yellow watchman goby/candy pistol shrimp pair along with softies, zoas, mushrooms and various cleaning critters. <<Look into neon gobies. Gobiosoma oceanops is one of my favorites, and has startling blue lines.  Read here: http://www.wetwebmedia.com/neongobies.htm.  They are great nano fish, although I'd worry about the other goby if your nano is very small..>> Thanks! P.s. Yes, within the next year they will all be going into a larger tank after I move. <<Why not wait, then? Larger=more/different stocking options.  Lisa.>>

Chromis Query ... id, comp., sel.   4/8/06 Hi Y'all, <Chris> I'm just wondering if you could clarify any differences in suitability/temperament with Chromis or point me towards somewhere I can find more info - I have checked the WWM pages and FAQs already (& other sources) but can't seem to find the answers I seek. <... What little we have should be in the coverage, subFAQs coverage by the genus, family: http://wetwebmedia.com/marine/fishes/part2.htm Scroll down to the Damsels, genus...> My query is specifically around the differences between Blue-Green Chromis (C. viridis?), Blue Chromis (C. cyanea?) and the Green Chromis (with black spot at base of pectoral fin?) (C. atripectoralis?) <These are the most common species associated with these names... though there are often others> I have seen recently Chromis labeled as blue Chromis which looked (in my humble opinion) nicer than the blue/greens, it is difficult to tell from the picture on your Chromis page but the fishies that I saw had markings similar to blue devil damsels around the eye - small black splotch/band - does this fit with how blue Chromis are generally marked? <Mmm, if you mean mis-marked, labeled and/or appearing, yes> The colour of these fishies was consistent with the deeper blue (as on your page) than the blue/greens.  How do I differentiate between blue/greens and greens - is this the Pec fin black spot? <Not definitive... unfortunately. Some batches, source locations have this spot, others no.> Mainly my query is around the temperament of these fishies and any variances amongst variety - I am planning three of a single species for my new tank (a month or two before I start stocking yet - still working on the lists!) They will be sharing the tank with 2 Black & white Clowns, a couple of Banggai Cardinals & either a Flame Angel or a Coral Beauty (being tempted by the Coral B here) along with mainly SPS coral. On the basis of aesthetic value I am leaning towards the Blue Chromis (assuming you confirm that the fishies I saw labeled as such with the eye markings are indeed likely to be Blue Chromis) however behaviour and temperament (particularly as these are damsels!) are more important to me as I want all of my charges to co-exist as harmoniously as possible! On this basis is there much to choose between the blue, green/blue and green? <Viridis are the easiest going, most likely to mix with its own species, others... Cyanea next, Atripectoralis last... though all three of these Chromis are far to the left in terms of the spectrum of Pomacentrid aggressiveness. The short answer here is I'd go with the Blue-greens if this were a concern. Bob Fenner> Many thanks as ever   Chris

Chromis sp. 10/30/05 I like Chromis hanui but I want to know if they are peaceful?  <Generally much more sociable than their other damsel cousins.>  And are the legal to get? <Consult your local authorities, depends on your location. Adam J.> 

Chromis!  9/28/05 Hey Aquatic Masters!   <Heeee! Not quite> I have a 175 gallon FO (bowed) tank. <Beautiful> I am considering getting a Foxface Rabbit, 2 Heniochus, Yellow Tang, Threadfin, Raccoon, and 5 or 7 Blue Chromis.  I have a 20 gallon quarantine tank the fish will be in for about one month before going to the main tank.  My question is, would 7 Blue Chromis be too heavy a load for a 20 gallon quarantine tank?   Thank you for your help, Dan <Mmm, better to go with two sets... one of three, the other of four... with a collection of good-sized PVC parts to duck into, away from each other. Bob Fenner>

Schooling Chromis - 9/14/05 Hello Robert and Gang (or Crew, whichever you prefer)! I have a 150 gallon tank and I was hoping to add a small group of Chromis viridis (5 fish) and Chromis cyaneus (3 fish). <Should be fine. I would maybe add the them all at once if your filtration can handle the load (likely if you aren't saturated fish wise) or I would add them in order you specified 5 Viridis and then 3-4 Cyaneus>  I've read on WWM, among other places, that these two species are more likely to form a shoal, or even school, when they feel threatened. <May shoal without bullying or predatory threats> I guess my question is: how aggressive of a fish will it take to threaten/frighten them into this behavior? <Likely a predator of some sort.> Would either of the damsel species Amblyglyphidodon aureus (Golden) or Dascyllus marginatus (Marginated) do the trick? <Not in my opinion but putting a fish or any animal under any amount of stress in a closed aquarium is just not proper in my opinion. Especially if just for aesthetics. Unfortunately, it happens all too often even at the top level. I don't mean to condescend or chastise, but I really have a hard time with actually accepting this type of configuration. We are all guilty of it at some level, though. Try to see if they will school before stress induced shoaling> Any other small, hardy fish come to mind? <For schooling I think your best bet is the Chromis. ~Paul> Appreciate you! -Trent Fish Stocking Density  09/13/2005 Hola. I read on the site that the general rule of thumb for stocking an "average" marine aquarium is around one cubic inch per five gallons (potential volume or actual volume?)<tank size volume> . Are you sure this isn't longitudinal inches (of a fish of "average" width) per five gallons? <I'm sure> I mean, this is the way I was taught when I first got into aquaria. Here's an example... Say you've got a 50 gallon marine aquarium (with good equipment, maintenance regimen, etc. -an "average" marine aquarium). Now, the way I was taught is that you can only stock this average tank with around 5 two-inch average-sized fish-let's say Chromis viridis-if you hold true to the 5 gallon per longitudinal inch rule. Although with the stocking levels suggested on WWM, you'd be able to stock around 15 two-inch Chromis (because a two-inch Chromis, on average, is probably only about 1/3 of an inch thick and therefore 3 two-inch Chromis amounts up to about two cubic inches of fish and your allowed to have 10 cubic inches of fish per 50 gallons, therefore 15 fish). <By cubic inch, I'm saying that if you had a one inch cube, you could easily compress a Chromis into it with room to spare.  Consider that a two inch long puffer carries more body weight than a two inch goby, so length of fish is not very realistic in this regard.  The more mass a fish has the more waste it will produce. So a two inch puffer is going to produce more waste than a two inch goby, and waste is what we are concerned with when establishing stocking levels.> I don't know about you guys, but 5 Chromis sounds like a more realistic number (although a little on the understocked side) than 20 for this tank. So do you think the "right" number of fish for this tank would be 5, 20, or somewhere in-between? <I would say ten Chromis' in a 50 would be safe> <<I wouldn't place more than 5... of easygoing species. RMF>> Thanks in advance for any help you can give, you guys are great. -Trent <You're welcome.  James (Salty Dog)>

Chromis Question 8/3/05 Hey all, Just want to say thanks for everything before I start. Great site, keep it up. Ok, I have a 27g tank. My inhabitants include 1 coral beauty and 1 sebae clownfish. <This is too small a system for this Centropyge> I would like to add some green Chromis in this tank, hoping they might school. Is this a good idea, considering the size of my tank. <Mmm, not really... some folks will disagree, but if this were the only species, you might do fine with a small grouping of (likely) C. viridis> If it is, how many and would I have enough space to put in 1 more fish, preferably a bicolor blenny.                                       Thanks <Bob Fenner>

Picking The Final Fish... 07/01/05 Hello Wet-Web Crew! <Scott F. your Crew member tonight!> Kudos to each of you for your continuing efforts. I thank you, and my fish thank you too!! <Glad to be of service! We're thrilled that you enjoy the site!> After reading up on the Blue-Green Chromis, I am wondering if you could advise if I should add these fish to my current set-up. I have a 90 gallon, 2 year old soft coral reef tank. It has about 90 lbs. of live rock. Presently, it is home to the following... 1 Royal Gramma, 2 Ocellaris Clowns, 2 Six-line wrasse, 1 Coral Beauty Angel and 1 Banggai Cardinal. Every one gets along swimmingly. (ha-ha -sorry).  I would like to add some of these Chromis, but how many? Based on the size of my tank, and population so far, what is your opinion? <Hmm...I think that you might be pushing it adding more than 1 or 2 Chromis. Since they seem to fare better in small groups (like 3 minimum), I'd pass on them at this stage.> If you think this is a poor option, I'm open to other stocking suggestions. I appreciate your input, and thank you sincerely, in advance.  Brenda  <Well, Brenda- I'm a big fan of smaller fish, like Blennies and Gobies. I'd look into neat fishes, like the Bicolor Blenny (Ecsenius bicolor), or The cute Yellow Clown Goby (Gobiodon okinawae). Both are small, relatively undemanding fishes that are a good example of the kinds of fishes that you should be looking at to round out your tank's population. Hope this points you in the right direction. Good luck! Regards, Scott F.> Fish compatibility 6/31/05 Hello Wet-Web Crew! Kudos to each of you for your continuing efforts. I thank you, and my fish thank you too!!  After reading up on the Blue-Green Chromis, I am wondering if you could advise if I should add these fish to my current set-up. I have a 90 gallon, 2 year old soft coral reef tank. It has about 90 lbs. of live rock. Presently, it is home to the following... 1 Royal Gramma, 2 Ocellaris Clowns, 2 Six-line wrasse, 1 Coral Beauty Angel and 1 Banggai Cardinal. Every one gets along swimmingly. (ha-ha -sorry)  I would like to add some of these Chromis, but how many? Based on the size of my tank, and population so far, what is your opinion?  If you think this is a poor option, I'm open to other stocking suggestions. I appreciate your input, and thank you sincerely, in advance.  Brenda  <Brenda, the Chromis' are a peaceful addition to your tank.  As far as stocking, I like to figure one cubic inch of fish per five gallons of water.  In your case that would be a total of 18 cubic inches of fish.  I like this method because actual body size is what you want to keep in mind, not length.  Of course you won't be able to come up with exact figures, but you should be relatively close.  With what you have in there now, an addition of three Chromis should pose no problems.  James (Salty Dog)>

Sending Chromis To School Bob:  (Or whomever :o) <Scott F. the "Whomever" tonight! Glad to be of service!> With regards to the Chromis family such as the blue-green: I would like to have a school of these in a 55g FOWLR tank - is this possible?  If so, what is the maximum population you would recommend (no other fish). Thanks, David <A monospecific (one species) display of Chromis would be hot! I'm stoked hearing about that! Chromis atripectoralis, the "Black Axil Chromis" can reach about 4 inches, and the "Blue Chromis", Chromis viridis, can hit over 3 inches, too. I'd figure that you could get away with about 5-6 individuals in a 55 gallon tank, but this might be pushing it a bit. If you leave a lot of room for them to swim (in other words, keep your rockwork low), they will school and behave in a much more natural fashion. Just keep the water quality high and the feedings frequent, and you'll be rewarded with a beautiful display! Enjoy! Regards, Scott F>

First Fish (11-17-03) Thanks. <No problem.> I have one more question. Would a Green Chromis be good in my tank if I put 2 of them in or no.<The Chromis should be fine but I would put 3 as odd numbers usually help distribute aggression.  On the other hand you also don't have a lot of room to work with.  You can find some more info at our site www.wetwebmedia.com.  Cody>

First Fish (11-21-03) Hello again, <Howdy> Sorry for all the questions. <No problem!> But would 1 Green Chromis be fine instead of 3 or do I need them in groups. This will be my final first fish question. If this won't work, would a yellowtail damsel be fine. Just 1 though.<You should be fine either way, just make sure the Chromis is eating well and active before you take him home.> Thanks

Chromis viridis School Size I've had my new reef tank for about 4 weeks now. 72 gallons.  We added 3 Chromis after about a week.  2 were doing very well and the third seemed to be getting picked on a lot.  I read that a larger school might lead to less bullying, so we added 3 more last week.  They are acclimating fairly well, but that one timid guy is still hiding a lot.  He does come out to eat a little bit, but then goes back to hide.  Do you think he just needs a little more time or should we get a 7th fish to make for the odd-numbered school?  Instinct tells me that adding a single fish to this mix is not a good idea for the newcomer. Thanks in advance. <I concur with you concerns and would hold off on adding any more Chromis to this system. Bob Fenner>

Other Chromis Schooling - 8/23/2004 Crew: This is a resend from last week (I totally understand things get lost). I am interested in the Black Bar Chromis (Chromis retrofasciata), and I was wondering if they are known to school in aquariums? <Mmm, not much... not as tightly by far as some of the more commonly offered members of this genus, e.g. C. viridis> While I am here, do most Chromis' school in aquariums (or the wild)?  Thanks, Rich <I'm guessing the propensity for schooling in the wild and captivity in this genus is split about midway... some are almost always found in close association in number, others more equidistant and reacting, challenging each other than moving in concert... much like Chrysiptera, or even Stegastes spp. damsels. Bob Fenner> Considering Chromis - 11/18/04 Mr. Fenner, <Paul in for Bob today!> I would like your input on these little guys. <Sure.> I have a 75 gallon with 120 pounds of LR and numerous softies. Currently I have a Percula, royal Gramma and a coral beauty. Tank has been up and running for over 6 years. Never wanted to get a big fish because of limited swimming space with so much LR. <Understand. A great idea regardless of tank size and swim room.> Thought about adding a few of these but were unsure of their temperament. <Well, actually, I preface my ramblings here with "this is purely my observations and opinions", but I find them to sometimes be quite aggressive even in a group of three. Also, they seem to have a bit of high mortality rating recently. Not sure if it is collection methods, poor acclimation at the wholesaler, poor fish stock in general or what. I have yet to get a stable batch in quite some time. We seem to keep the ones that live and try (emphasis on try) to add them together from different schools as they die off.> Will they get along with my other fish? <They should have little problems with your fish selection in my opinion.> Are they hardy? <Loaded question, but I would say they have been in the past but as I stated above, lately, the places I have seen, wholesaler/retailer outlets they have a high mortality rate currently.> How many would you add? <To your tank? I would say about 9-11 (odd numbers preferable) I was told they school and should add anywhere from 3 to 8. <Oh, you could easily make them the premiere display of your tank. They look awesome schooling, again though, they do seem to get a bit nippy and aggressive to each other in smaller schools. As a matter of fact, I would try adding like five at one time and then maybe another three a month later then add another three a few weeks after that. You will likely lose a few. Get them young, (Important, that they are on the small and healthy side) and from a quality store. Quarantine them if possible or see if the store can do it for you. (if possible) Acclimate them slowly to your tank, keep water quality high, and then wait for a month before adding another school. Just don't want to stress your bio filtration with too big of an addition at one time. Let me know your findings and if it works out send a pick of them schooling. Do use the internet as a tool and see what others are saying. Check forums and other articles in various books, too. Don't rely too much on one source. Hope this helps. Thanks for participating here at WetWebMedia. ~Paul> This is why I'm asking. Thank you Ken How many green Chromis - 6/2/05 I have a 30g saltwater tank with 20lbs of live rock and 2 false perc clowns, 1 watchman goby, 14 hermit crabs, 3 snails, and 2 cleaner shrimp...was thinking of adding a small school or green Chromis...not too many because I also want to add a flame angel or royal Gramma in the future <Easy question for me. I might catch some flack but this is from my experience....I would not add a single Chromis or flame and go for the Gramma. The flame angel will get fairly large for such a small tank and sometimes will bully. The Chromis can be sensitive and would need to be added as an odd number grouping. Just a lot of stress if they are not real healthy. Quarantine is always necessary. The grammas stay relatively small and are quite hardy. Captive bred is usually best.> ...my question is what would be a good amount of green Chromis to add without over crowding my current tank so I can add at least one more if not 2 more in the future? <Go for the Gramma. Keep the fish small. Chromis tend to in-fight and if you must add Chromis then I would add 3-5 no more, no less. No flame in my experience. Gramma if you don't add the Chromis. A lot to think about but you will be glad as you will likely suffer less frustration from death and have room for the inhabitants. Thanks for being part of it all. ~Paul> - Green Chromis - Hello,  <Hello.>  I currently have 2 green Chromis about 2.5 inches that pick on each other quite a bit, I would like to add 5 more to give me a small school but all I can find are small (1-1.5 inches) would the larger established ones kill the new smaller ones or would they school?  <I don't think so on both counts - Chromis are generally social fish and not nearly as aggressive as their Damsel relatives, so I think you add some more Chromis and in spite of their size things will go well. On the other hand, for reasons as yet undetermined, Chromis do not school so well in captivity - they form loose groups, but will not form tight schools.>  I have seen mixed size schools while diving but of course the living space was unlimited.  <And the predatorial pressure much higher... they are well aware of their environment and do not form these same schools in captivity.>  I do not want to buy more just to have them killed. Thanks Mike W. <Cheers, J -- > 

Chromis a good next choice?         Hello everyone. Hope you all had a nice Christmas/ Holiday. <So far...> I was wondering what some of your thoughts might be to me adding 2 or 3 smallish green Chromis to my 55 Ga. I currently have one 2 inch blue tang, one 2" yellow tang, a small blue devil damsel who minds her own, a 2" coral beauty and two false perculas. <Mmm, with growth your tank is pretty much full... and the blue devil may become more so with other damsels present... but if your system were about twice the size, these would be a good choice> I am definitely upgrading to a 120 in the next 6 months to a year. <Oh! Bingo! I'd wait till then to add them> I am running an Eheim 2215 and a CPR Bak Pak skimmer with 30 pounds of live rock which will soon be 50 to 60 lbs. Comments?? Too much bio-load an issue, I think I'm on the verge but is it possible? Ands also will the Chromis and my 1" damsel co-habitat? Much thanks as always.         -Heather <Bob Fenner> Chromis mixing hello! <Hi,> I was wondering in a 150 gallon tank or a 125 gal. tank if you could mix 3 green Chromis and 3 blue Chromis together peacefully?  <Yes, they should get along peacefully.>  If so would they school together or school according to their species?  <It depends on the other tank mates.  If the Chromis are threatened they will school together as a defense mechanism (survival in numbers).  If not then they won't school at all.> Oh, and 1 more question, what's your favorite fish for fresh <Motoro Stingray> and saltwater? <Clown Trigger, or BlueLine Trigger I can't decide.> thanks again!! <No problem, MikeB> Chase

Protein Skimming Bob, I have a question about skimming. I recently upgraded my protein skimmer. I bought a Remora C (the water injection type). I have had it for a week and it has collected 4 times more nasty stuff than my old skimmer. I have had a little trouble with hair, green and red and algae. With this new skimmer I seem to be collecting a lot of green stuff. Will there be change in color of junk in my collection cup eventually? <Interesting question. Yes, likely> When I go to my LFS usually what is in there collection cup is brown thick stuff. I wondering if there is a cycle where all of the green algae disappears then the red algae will disappear. <There is, are... but there are definite different "skimmable make-ups" of different systems... much has to do with the types of life kept, foods/feeding, lighting, other filtration, type of seawater used, type/make of skimmer/technology...> I know I made the right move in purchasing this skimmer because of what it is producing and my water seems to be a lot clearer. I was told the best way to get rid of red algae is to lower the nutrient levels and skim it out. The hair algae I can deal with. Thanks for all of your help. One more question is it OK to have one green Chromis or do you absolutely need 2 or more? <More is better... social animals. Bob Fenner>

Chromis vanderbilti  Hi gang! <Howdy Ted> I have a compatibility question. My LFS just got in a bunch of Vanderbilt Chromis and I think they're the neatest looking guys - much prettier in person than pictures. I would like to get a school of 5 but am not sure if that's too much for my tank and inhabitants. I've got a 55g tank with a pair of ocellaris, 6line wrasse, and a orange spotted goby (there's about 70 lbs live rock and 4 LPS - just to give an indication of how much space is taken up). Will they get along with the clowns since they're both of the same family? If that doesn't work is a fairy wrasse compatible with a 6line? <Mmm, had to go take a look at my pix, coverage: http://www.wetwebmedia.com/chromis.htm  What little I know re this species is actually stated there in a couple of sentences. I'd try a group of three individuals... hard to say re the current occupants getting along with the newbies... Some Clownfish species, specimens can be pure terrors territorially in such small volumes (a fifty five)... and do keep your eye on the six-line for the first few days... the species can also be troublesome. I would leave off with mixing in a Cirrhilabrus sp. here. Bob Fenner> Thanks in advance and have a great day! Ted

Green Chromis (numbers of the beasts) Dear Bob, A friend read that you should keep these fish in groups but only in odd numbers. Why???? <Sometimes called the "locker room effect" (by me at least), even numbers seem to lead to more fighting, bullying... between individuals. Having the "odd fish" results in having a bit more rest, ability to hide from the alpha individual/s> I have 5 in a shoal with no problems. He had 6 but one was attacked by the remainder and died. <Not atypical... but could be that the others had just already established territories that their resource would allow... no more room for another> Is the theory of odd/even numbers proven. It has certainly caused debate at my LFS (UK Marines -Roy Meeke) <No progress without conflict... not me this time, Nietzsche. Bob Fenner> Any answers would be appreciated. Kindest Regards, Stephen Tope

Re: Green Chromis Dear Bob <Steve> Many thanks for the prompt reply. I am busy upgrading to a 200 gallon system with 80 Gallon plenum sump. What number would be a good shoal for a tank of this size? <Five, seven, nine> They will be housed with 2 x Maroon Clowns, 1 Sixline Wrasse, 2 Lipstick Tangs, 3/4 Yellow Tangs, 1 Flame Angel and a couple of gobies. I am looking to make an impact with them. <Put them in first> Regards, Steve Tope <Be chatting my friend. Bob Fenner>

Chromis agilus Dear Bob: I have downloaded some of your wonderful pics you took in Hawai'i of the genus Chromis, and have been really trying to find a place to get 3 of the Chromis agilus for my 60 gallon reef tank. They would be the "stars" as the 3 other fish are 1 clownfish, 1 pygmy angel and 1 royal Gramma. I have tried all public sources and they are unwilling or unable to order these fish for me. Is there someone in Hawai'i you know who might ship to me, or someone here in California or elsewhere who has a contact. <Mmm, yes... have your shop, supplier contact Quality Marine or Underwater World in Los Angeles... they have regular HI shipments (weekly) and good rapport with collectors, may be willing to have their collectors send you some... though few of the Damsel species are collected from the 50th State (not enough pay to merit it... and the common techniques of capture and holding impose high mortalities on these fishes... or you might try Randy Fernley of Coral Fish Hawai'i... who has a nice retail shop on O'ahu and is a great collector...> I will be there over Xmas for my second wonderful visit, but don't think it possible to walk into a pet shop there and carry them on the plane.  <You could if someone had them.> I do look forward to snorkeling though and have your note to someone else who is going there soon. I am still painting and my next ptg is that calendar fish from last week, who thanks to you, is named Lorenzo. <Great!> My best - great diving, great pics. Connie Cavan <Many more to come my friend. Contact us when you're closer to Southern Calif. Bob Fenner>

Chromis agilus Dear Bob: Welcome back to the real world! <Yeeikes! Don't know if I can take it (Ha!)> I called Randy Fernley at Coral Fish in Hawaii and he was very helpful. I'm faxing him your photo of above fish and he said he'd have them for me (or would try to) when I am there at Xmas. <Great... his "pet name" is "Furry Slippers" (okay, mine is "Dogfish"... but Earl Kennedy's is "Lollipop"!). Randy is a fine person... and a great diver and asset to the trade.> I'm going to ask him to FedEx them to me if he gets them sooner. I gather he does his own diving. Fantastic! The fish stores here in San Francisco are really way below par for a city that "has it all". <Am surprised... there's a new one (can't remember the city, but an industrial park... with great walnut-like tank frames...) and a bunch of nice ones out in Sacto...> Thank you so much for following through. If the event happens, I will certainly let you know. <Hotay> My best wishes for you and the others who work so hard on your fabulous (really) website. Mine is listed above and is pretty much what one would see in St. Thomas, except for my fish project. I am up to ptg #3, named Lorenzo for some strange reason. Connie Cavan <How about Bob? Not the movie silly. Bob Fenner>

Chromis  Hi to all of you-I have another question. One of you suggested to me that because of the size of my tank (60 gallons) that Chromis would be a good option. I have downloaded pictures of some gorgeous Chromis - one is Chromis agilus and the other is Chromis ovalis. I cannot locate these fish anywhere- the viridis are available. I want to order three of them and have tried every online fish-selling place that advertises or that I have heard of. Is there somewhere I can order these fish directly or are they unavailable or what.  <both occur in Hawaii and although somewhat uncommon, at least the ovalis has been available in the recent past with regularity.> They are Bob's pictures, and the agilus is really beautiful. Thanks in advance for any help you can give. Connie Cavan <have you tried the Marine Center or Flying Fish Express? As you look for dealers... seek someone with a good Hawaiian or Micronesian connection (evidenced by C. multicolor angels, bicolor Anthias, Naso tangs, black tangs, potters angels and the like in stock) Best regards, Anthony>

Chromis and Calcium Dear Bob & WWM crew, <cheers> You have helped me avoid heaps of learning through "experience". I've found that most journeys are less stressful when a map can be used... thanks for the "map". <with pleasure... do pass your wisdom along in kind> I want to add 5 small Chromis viridis to my 55 gal reef (48in.) and would like to know if this might be too much stress on the bioload or territory partitioning? <fine and peaceful fishes... they will fit with your below listed bio-load very well> The system includes 50lbs live rock, 2" fine sandbed & Reef Devil skimmer in sump. The bioload includes: 1 Brazilian Gramma, 2 Ocellaris, 1 Banggai, 4 serpents, 1 Sand Star, 1 Cleaner shrimp and various LPS & soft corals. Also, other than Kalkwasser, what additive will help raise pH without building much alkalinity? I'm running 7.9 to 8.1, the tank looks good, should I concern myself? Your thoughts would be appreciated! <I find Kalkwasser to be the very best at this with added benefits of saponification (improved skimmer performance) and phosphate precipitation. Best regards, Anthony>

Chromis schooling question Hello again crew, thanks for being there for us! <Our pleasure!> I am planning on purchasing about 5 green Chromis for my 135 gallon FO tank, in hopes that they will form a small school.  When looking at vendors online, I notice there is also another Chromis, the Half and Half Chromis, that is the same size, just a bright orange color. Two questions:   1) Will the green Chromis school readily? <We can never say definitely with any fish but your chances are very, very good> If not, could you recommend another small, peaceful fish? <Chromis are good> 2) If I were to mix the two species, would they school together?  I'm guessing not, but it might be interesting to get varying color in the group. <My instinct says "No" but I won't commit on this question. I'm just not sure. Fish have been known to act in ways not characteristic in the ocean. Look in several stores and see if you can find different schooling combinations. David Dowless> Jim

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