Do green chromis kill eachother in schools?

criticle · 01/12/2007, 03:44 PM

I turned on my lights this moring to find, one of my three green chromis on the sand dead. I saw an injury in front of his dorsal fin and theres nothing else in the aqaurium to hurt it. Is it common for chromis to attack eachother in schools?

Obi-dad · 01/12/2007, 03:48 PM

This happened to me when I had 3 in a 29g tank. They picked on the smallest one, it died. Then the bigger one left picked on the smaller one until it died. This happened over a period of months though. If yours are new then the death might be due to other causes.

criticle · 01/12/2007, 03:52 PM

No, Ive had the the three for two and a half weeks now and I suspect that both bigger chromis attacked it.

AndyB4784 · 01/12/2007, 04:10 PM

three chromis is not a school. i'd say that the MINIMUM number for a school would be 6 however i'd go with about 10 for a nice school. take the remaining chromis out and return it or add 4+ more.

Hop · 01/12/2007, 04:14 PM

Occasionally they do. I had a group of nine and one, by one, three were singled out and killed. The remaining six are fine.

There was a thread not too long ago about this and some people had zero problems and others had the same experience as I did

HBtank · 01/12/2007, 04:45 PM

I think most descriptions of Chromis are wrong, they seem to overlook they aggression they can and will show towards their own species at times.

Almost every description says they are a "peacefull schooling fish".

My blue chomis is anything but that. Not only will it go on a rampage towards other chromis, but it is pretty aggressive all around.

I think that as juveniles and packed together they might be, but full grown and in a medium sized aquarium, not at all for me.

notyet · 01/12/2007, 06:23 PM

what else is in the tank with them?

schooling is a defensive response to potential threats. if there are bigger/aggresive fish in the tank the chromis will rely on the school for a sense of security. if there are no potential threats, the "school" may turn on each other...

at least that is my understanding...

jeffhaag · 01/13/2007, 07:43 AM

I've had 8 grene chromis in my tank for over 2 years. I have always had huge problems with acclimating chromis and have probably seen a 30% loss rate in my two tanks within the first 2 weeks. They will develop pink fleshy spots on them and die almost within a day of getting the spots. Once they make it through the first 2 weeks though, I have never lost one that didn't jump from the tank. I think it has to do with poor capturing techniques and shipping techniques. Afterall, how much care do you think they take of a $5 fish. I do not have these problems with any other fish I have aquired and tank parameters are perfect on both of my tanks.

davocean · 01/13/2007, 11:35 AM

I've had the same 6 chromis for over 4 years now w/ no problems.
Model citizens, and help bring out shy fish.
Mine have even adapted to enter both my nems.

tkeracer619 · 01/13/2007, 12:07 PM

None of my blue/green chromis in a year have been lost due to agression. One died in qt and one jumped. Now im down to 7.

they have never attacked each other that I can tell.

They did school a lot more before I removed a grumpy 3 stripe damsel. Now they hang out in my corals and school during feeding.

Snakebyt · 01/13/2007, 04:41 PM

i had 7 and they slowly one by one disappeared till there were none

ReeferAl · 01/14/2007, 01:11 PM

There's no question they can be aggressive and territorial to each other. I've noticed that the fighting is considerably lessened when I feed more in volume and frequency.

Allen

evilsike · 01/14/2007, 01:42 PM

I have 6 blue/green chromis in 3 years now and yea, they are model citizen in my tank. my mandarin was really shy and like one posted above, it brings out the shy fish. I do see they chase each other once in a while but not bad. they stop chasing after a foot.

01/12/2007, 03:44 PM	#1
criticle Registered Member Join Date: Nov 2006 Location: Florida Posts: 64	Do green chromis kill eachother in schools? I turned on my lights this moring to find, one of my three green chromis on the sand dead. I saw an injury in front of his dorsal fin and theres nothing else in the aqaurium to hurt it. Is it common for chromis to attack eachother in schools?

01/12/2007, 03:48 PM	#2
Obi-dad Registered Member Join Date: Feb 2003 Location: CT Posts: 4,314	This happened to me when I had 3 in a 29g tank. They picked on the smallest one, it died. Then the bigger one left picked on the smaller one until it died. This happened over a period of months though. If yours are new then the death might be due to other causes. __________________ Greg, member of ARKSC and CTARS Visit our CTARS club website by clicking my RC name then 'visit homepage' - and please support your LFS Current Tank Info: 75g mostly stonies. DIY LEDs (24 CW XP-G, 48 RB XR-E) on dwizum CAT4101 drivers, DIY Hydra controller, SSB, Korallin Ca Reactor, Euroreef skimmer

01/12/2007, 04:14 PM	#5
Hop Carpe Noctem!!! Join Date: Jul 2004 Location: Western Colorado Posts: 8,548	Occasionally they do. I had a group of nine and one, by one, three were singled out and killed. The remaining six are fine. There was a thread not too long ago about this and some people had zero problems and others had the same experience as I did __________________ Hop Current Tank Info: 300-gallon in-wall system (mixed reef)

01/12/2007, 04:45 PM	#6
HBtank Premium Member Join Date: Jan 2006 Location: Huntington Beach, CA Posts: 2,957	I think most descriptions of Chromis are wrong, they seem to overlook they aggression they can and will show towards their own species at times. Almost every description says they are a "peacefull schooling fish". My blue chomis is anything but that. Not only will it go on a rampage towards other chromis, but it is pretty aggressive all around. I think that as juveniles and packed together they might be, but full grown and in a medium sized aquarium, not at all for me. __________________ 80g Aiptasia dominated reef tank.. with fish and now a bunch of berghia! Current Tank Info: 80g tank, re-starting a reef after a zoanthid nudibranch plauge, followed by months of steady and unstoppable STN/RTN, crashed; stayed FOWLR for a couple years, currently an aiptasia dominated reef tank with fishies and BERGHIA

01/13/2007, 11:35 AM	#9
davocean Registered Member Join Date: Nov 2005 Location: San Diego, CA Posts: 14,655	I've had the same 6 chromis for over 4 years now w/ no problems. Model citizens, and help bring out shy fish. Mine have even adapted to enter both my nems. __________________ There's a fine line between owning your tank and your tank owning you! Current Tank Info: SCA 120g RR Starfire, Tunze silence 1073.02 return, 40g sump w/ fuge, SWC Extreme 160 cone skimmer,Geismann reflexx 4xT5, 2x Panorama Pro LED strips, Vortech MP40QD

01/12/2007, 03:52 PM	#3
criticle Registered Member Join Date: Nov 2006 Location: Florida Posts: 64	No, Ive had the the three for two and a half weeks now and I suspect that both bigger chromis attacked it.

01/12/2007, 04:10 PM	#4
AndyB4784 Registered Member Join Date: Jun 2006 Location: lansing, mi Posts: 309	three chromis is not a school. i'd say that the MINIMUM number for a school would be 6 however i'd go with about 10 for a nice school. take the remaining chromis out and return it or add 4+ more.

01/12/2007, 06:23 PM	#7
notyet Registered Member Join Date: Aug 2006 Posts: 44	what else is in the tank with them? schooling is a defensive response to potential threats. if there are bigger/aggresive fish in the tank the chromis will rely on the school for a sense of security. if there are no potential threats, the "school" may turn on each other... at least that is my understanding...

01/13/2007, 07:43 AM	#8
jeffhaag Registered Member Join Date: Feb 2003 Location: Chickamauga, GA Posts: 442	I've had 8 grene chromis in my tank for over 2 years. I have always had huge problems with acclimating chromis and have probably seen a 30% loss rate in my two tanks within the first 2 weeks. They will develop pink fleshy spots on them and die almost within a day of getting the spots. Once they make it through the first 2 weeks though, I have never lost one that didn't jump from the tank. I think it has to do with poor capturing techniques and shipping techniques. Afterall, how much care do you think they take of a $5 fish. I do not have these problems with any other fish I have aquired and tank parameters are perfect on both of my tanks.

01/13/2007, 12:07 PM	#10
tkeracer619 Registered Member Join Date: Jan 2006 Location: Westminster, CO Posts: 17,289	None of my blue/green chromis in a year have been lost due to agression. One died in qt and one jumped. Now im down to 7. they have never attacked each other that I can tell. They did school a lot more before I removed a grumpy 3 stripe damsel. Now they hang out in my corals and school during feeding. __________________ Hobby Experience: 9200ish gallons, 26 skimmers, and a handful of Kent Scrapers. Current Tank: Vortech Powered 600G SPS Tank w/ 100gal frag tank & 100g Sump. RK2-RK10 Skimmer. ReefAngel. Radium 20k.

01/13/2007, 04:41 PM	#11
Snakebyt Registered Member Join Date: Aug 2000 Location: Lubbock Tx Posts: 2,141	i had 7 and they slowly one by one disappeared till there were none

01/14/2007, 01:11 PM	#12
ReeferAl Premium Member Join Date: Dec 2001 Location: Fond du Lac, WI Posts: 2,040	There's no question they can be aggressive and territorial to each other. I've noticed that the fighting is considerably lessened when I feed more in volume and frequency. Allen

01/14/2007, 01:42 PM	#13
evilsike Registered Member Join Date: Aug 2005 Location: New Jersey Posts: 427	I have 6 blue/green chromis in 3 years now and yea, they are model citizen in my tank. my mandarin was really shy and like one posted above, it brings out the shy fish. I do see they chase each other once in a while but not bad. they stop chasing after a foot. __________________ All experts were once a beginner Current Tank Info: 46 Gal bow front, Aqua C 120, 10g sump w/ 6"x10" refuge, 5x39 T5, AC2, 2xmodded mj