Blue Green vs Green Chromis

davidryder · 07/06/2007, 11:00 AM

I've been doing some thinking since the first time I heard about Chromis killing each other off. I thought this was strange as I've had 2 schools of them in 2 separate tanks with no problems... and all the books I have read say Green Chromis make a great schooling fish, and are the most peaceful of damsels.

There are two type of chromis... I wonder if the success rate has something to do with the species. There is the Chromis viridis (Blue green chromis) and the Chromis atripectoralis (Green Chromis). They look the same to me in my book except the green chromis has a black spot on the inner base of its pectoral fin. From wet web media:

"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"

I can't find much more info on that matter...

I also thought it could have to do with the size of the tank. I've had a 125 and now a 90 and a school of 7 and 5 respectively and I've never had one die - and I've also had the Blue Green Chromis both times.

The other factor I was considering is the size of the individual fish. I've read that as long as they are all generally the same size there shouldn't be a problem.

Anyway I wanted to get some feedback... maybe someone has some more info.

King-Kong · 07/06/2007, 11:20 AM

Tagging a long to see if anyone knows more.

J. Montgomery · 07/06/2007, 12:00 PM

LFS owner told me that for whatever unknown reason, they do better when kept in odd numbers. He told me that when you have even numbers (4 or 6) that one of them tends to get singled out and killed. Thats just coming from his experience of >20yr.

gsbobcat · 07/06/2007, 02:39 PM

I've had 3 blue-greens that I bought about 3 mos. ago and they swim all over together w/ no problems.

ahullsb · 07/06/2007, 02:43 PM

I have 5 that have been fine so far for a month or two. Thats not long enough to say for sure that they will be alright in the long run, but I was told they do better in odd numbers as well. I am taking a guess, but I would imagine they would be less likely to go after each other if they don't feel like they are competing for food, or space. I feed my tank twice a day so maybe that is helping? They are also the blue/ green type, and I think they are really cool to look at.

killagoby · 07/06/2007, 02:50 PM

Never had luck with my blue/green Chromis. I started with a school of about 5 or 6 of them over 3 years ago. They've since dwindled down to one. The one in my tank now actually kept attacking and eating at the others, who eventually died.

oct2274 · 07/06/2007, 03:01 PM

i bought 3 and i'm down to one as well. He just doesn't like other chromis, but is a total wimp when it comes to the other fish in the aquarium.............

three-spot · 07/06/2007, 03:25 PM

I bought 3 and am down to zero...

MrSpiffy · 07/06/2007, 03:36 PM

Funny you should bring this up! I just read in the latest issue of Tropical Fish Hobbiest an article about this very thing. The recommended species of chromis was Chromis viridis (blue-green chromis).

The article stated that C. atripectoralis looks very similar to C. viridis, but it gets about an inch larger, has the "black pectoral axil" is more widely distributed in the wild, is often misidentified as C. viridis, and "this species is considered even more peaceful than C. viridis". But C. viridis was the recommended type of chromis to keep.

Now, I'm not sure which one would be best, since they're both considered peaceful, considering they're damsels, really. But there are several other types of chromis that could potentially cause problems in aquaria. I'm guessing that it all boils down to individual personalities, as we often see in all other types of creatures we try to keep.

Hope that helps! (Probably not, but you never know

)

07/06/2007, 11:00 AM	#1
davidryder Claris or Elliot? Join Date: Apr 2005 Location: Nightopia Posts: 2,750	Blue Green vs Green Chromis I've been doing some thinking since the first time I heard about Chromis killing each other off. I thought this was strange as I've had 2 schools of them in 2 separate tanks with no problems... and all the books I have read say Green Chromis make a great schooling fish, and are the most peaceful of damsels. There are two type of chromis... I wonder if the success rate has something to do with the species. There is the Chromis viridis (Blue green chromis) and the Chromis atripectoralis (Green Chromis). They look the same to me in my book except the green chromis has a black spot on the inner base of its pectoral fin. From wet web media: "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" I can't find much more info on that matter... I also thought it could have to do with the size of the tank. I've had a 125 and now a 90 and a school of 7 and 5 respectively and I've never had one die - and I've also had the Blue Green Chromis both times. The other factor I was considering is the size of the individual fish. I've read that as long as they are all generally the same size there shouldn't be a problem. Anyway I wanted to get some feedback... maybe someone has some more info. __________________ A rolling stone gathers no moss... Current Tank Info: 90g mixed reef, corner overflow (Mag 9.5), 25g refugium (Mag 5), 15g refugium, Orbit 260w pc, Pan World 50PX-X (Closed loop), AquaC EV-120 (now skimmerless)

07/06/2007, 12:00 PM	#3
J. Montgomery Mouth Pipetting Join Date: Aug 2006 Location: Charlottesville, VA Posts: 6,278	LFS owner told me that for whatever unknown reason, they do better when kept in odd numbers. He told me that when you have even numbers (4 or 6) that one of them tends to get singled out and killed. Thats just coming from his experience of >20yr. __________________ Josh

07/06/2007, 02:43 PM	#5
ahullsb Registered Member Join Date: Sep 2006 Location: sacramento, ca Posts: 2,729	I have 5 that have been fine so far for a month or two. Thats not long enough to say for sure that they will be alright in the long run, but I was told they do better in odd numbers as well. I am taking a guess, but I would imagine they would be less likely to go after each other if they don't feel like they are competing for food, or space. I feed my tank twice a day so maybe that is helping? They are also the blue/ green type, and I think they are really cool to look at. __________________ Andy Sacramento, CA Current Tank Info: 55 gallon reef w/20 gallon sump/ER135/ 75 pounds of live rock, 4 in sandbed, 2 b&w ocellaris clowns, yellow watchman/pistol, rosy scaled wrasse, Mystery wrasse, Copperbanded Butterfly, Lighting 48" outer orbit 2 150 mh/ 4 t5 actinics

07/06/2007, 02:50 PM	#6
killagoby Registered Member Join Date: Jun 2005 Location: Monroe, NJ Posts: 2,150	Never had luck with my blue/green Chromis. I started with a school of about 5 or 6 of them over 3 years ago. They've since dwindled down to one. The one in my tank now actually kept attacking and eating at the others, who eventually died. __________________ How much money did you spend on that rock again?

07/06/2007, 03:25 PM	#8
three-spot Registered Member Join Date: Aug 2006 Location: windsor, ontario, canada Posts: 201	I bought 3 and am down to zero... __________________ Julian

07/06/2007, 11:20 AM	#2
King-Kong Registered Member Join Date: Oct 2004 Location: Gainesville, FL Posts: 2,346	Tagging a long to see if anyone knows more.

07/06/2007, 02:39 PM	#4
gsbobcat Registered Member Join Date: Apr 2007 Location: Green Springs, OH Posts: 52	I've had 3 blue-greens that I bought about 3 mos. ago and they swim all over together w/ no problems.

07/06/2007, 03:01 PM	#7
oct2274 Registered Member Join Date: Feb 2006 Location: Plano, TX Posts: 2,347	i bought 3 and i'm down to one as well. He just doesn't like other chromis, but is a total wimp when it comes to the other fish in the aquarium.............

07/06/2007, 03:36 PM	#9
MrSpiffy Premium Member Join Date: Apr 2006 Location: Loveland, CO Posts: 1,300	Funny you should bring this up! I just read in the latest issue of Tropical Fish Hobbiest an article about this very thing. The recommended species of chromis was Chromis viridis (blue-green chromis). The article stated that C. atripectoralis looks very similar to C. viridis, but it gets about an inch larger, has the "black pectoral axil" is more widely distributed in the wild, is often misidentified as C. viridis, and "this species is considered even more peaceful than C. viridis". But C. viridis was the recommended type of chromis to keep. Now, I'm not sure which one would be best, since they're both considered peaceful, considering they're damsels, really. But there are several other types of chromis that could potentially cause problems in aquaria. I'm guessing that it all boils down to individual personalities, as we often see in all other types of creatures we try to keep. Hope that helps! (Probably not, but you never know )