Hey guys, I had 3 blue green chromis in my 40 gallon for about 4 months and just noticed tonight I'm down to 2 left. They never really had that schooling behavior but also never noticed much aggression until tonight where the larger of the two chased the small one around the tank for three laps. It was during feeding time so were they just competing for food or should I move the big one to my 60 gallon tank so I dont lose another life?
Blue green chromis aggression
- Thread starter Applegate
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6 becomes 1. Classic chromis problem.
Anecdotally I have heard of 3 people that had a shoal (they don't really school) remain alive for more than a year. Out of hundreds of people that ended up with just 1.
The 3 success stories had a 110+ tank.
Remote possibility of springeri or talbots damsels cooperating.
Or it could be just another hoped for myth.
In any case, your 40 is way to small to expect success.
Sorry about that.
Anecdotally I have heard of 3 people that had a shoal (they don't really school) remain alive for more than a year. Out of hundreds of people that ended up with just 1.
The 3 success stories had a 110+ tank.
Remote possibility of springeri or talbots damsels cooperating.
Or it could be just another hoped for myth.
In any case, your 40 is way to small to expect success.
Sorry about that.
Sarah24!
2500 Club Member
Hello,
I have had seven now in my 240 for about a year now and they do school and usually very little aggression. The difference though is I have a Lt. Tang and anytime there is any form of aggression in my tank. He kinda tails slaps them across the tank. The 7 have to stay together because if not the paired clown fish will chase them, but only in singles. Which then the Lt tang goes after the clowns.
I would suggest adding to the number of 5 or 7 and make sure half are larger than him and the others equal or a tad smaller. This should help and you can also try a mirror for the larger one.
I have had seven now in my 240 for about a year now and they do school and usually very little aggression. The difference though is I have a Lt. Tang and anytime there is any form of aggression in my tank. He kinda tails slaps them across the tank. The 7 have to stay together because if not the paired clown fish will chase them, but only in singles. Which then the Lt tang goes after the clowns.
I would suggest adding to the number of 5 or 7 and make sure half are larger than him and the others equal or a tad smaller. This should help and you can also try a mirror for the larger one.
I had my fair share of blue green chromis (from 9 to 1). We all have that schooling beautifully in our tank. From what I learned, they will school when they feel threaten. My when from 9 to 5 and stayed schooling after I added six-line wrasse. When six-line wrasse decided not to care, chromis went from 5 to 1. Once a damsel, always a damsel. I've heard only Great barrier reef chromis will not kill each other off (from Mr. Saltwater Tank).
DangerDave
Valuable Member
I’ve had 7 chromis in my display for over a year, all still there. I just added 3 more a few weeks ago and they’re doing well so far.
Sarah24!
2500 Club Member
Hello,
From the tanks I have studied and observed for my thesis (a few years ago or tad more), I had great luck when there was a tank boss. Naso tangs were to nice but Lt tangs or purple tangs yellow tangs sohal, etc always keep them together.
Like I said it would be interesting to know those who had issues what size of tank, feed schedule, and tank mates. Now I have of the 7 some great big fat ones, and some that haven’t grown, but when I feed which is daily I feed in all three sections of my tank so they don’t have to fight for food. Just some ideas to help those others and, mine school often but there are times I only see four or three and I’m like crap. Then food comes and all seven are there, but if any of the larger ones in my 240, pick a fight with one of my tangs they all group together. Usually when that happens it’s doesnt matter with the Lt tang he plows after all of them. They scatter and come back in a group and he will chase them around the tank until they are exhausted.
Then though when that happens my huge Naso gets involved and goes after the Lt tang. I have yet see any go after him, well my female clown did and she slapped her across the tank twice. Which I think (she passed recently) is why her husband is alone in the frogspawn. She became too aggressive and well she nipped the wrong tang.
@DangerDave make sure you always always always keep an odd number. The even numbers will cause much higher aggression from all my experiments.
From the tanks I have studied and observed for my thesis (a few years ago or tad more), I had great luck when there was a tank boss. Naso tangs were to nice but Lt tangs or purple tangs yellow tangs sohal, etc always keep them together.
Like I said it would be interesting to know those who had issues what size of tank, feed schedule, and tank mates. Now I have of the 7 some great big fat ones, and some that haven’t grown, but when I feed which is daily I feed in all three sections of my tank so they don’t have to fight for food. Just some ideas to help those others and, mine school often but there are times I only see four or three and I’m like crap. Then food comes and all seven are there, but if any of the larger ones in my 240, pick a fight with one of my tangs they all group together. Usually when that happens it’s doesnt matter with the Lt tang he plows after all of them. They scatter and come back in a group and he will chase them around the tank until they are exhausted.
Then though when that happens my huge Naso gets involved and goes after the Lt tang. I have yet see any go after him, well my female clown did and she slapped her across the tank twice. Which I think (she passed recently) is why her husband is alone in the frogspawn. She became too aggressive and well she nipped the wrong tang.
@DangerDave make sure you always always always keep an odd number. The even numbers will cause much higher aggression from all my experiments.
FMF0331
Valuable Member
Started of with 20 of them , now down to 5
Looking to rid them all with a fish trap. All they do is fight each other over food ( i feed heavy - 3 x daily ) and sometimes go after my other fish.
Looking to rid them all with a fish trap. All they do is fight each other over food ( i feed heavy - 3 x daily ) and sometimes go after my other fish.
Haydn
Active Member
Many of the problems with 'green', blue-green' chromis being hit and miss is we are talking about more than one species of fish. I have seen for sale in UK LFS, Chromis viridis and C. atripectoralis both being sold as green chromis. C. viridis will live as a group (I hate the 'shoal' word) and I suggest those who report success have those. C. atripectoralis tend not to tolerate each other and if you are unlucky enough to get a mix of C. atripectoralis and C. viridis then you have no chance.
Just to add to the confusion there is another one, C. caerulea, which looks like 'green chromis' although I have never positively identified these in a LFS which doesn't mean they are not readily imported.
Confusion added to confusion, in May 2017 a new species Alelia’s Damselfish (Altrichthys alelia) was discovered- and guess what it looks just like a 'green chromis'.
So guys which species of green chromis do you have
@Chavin20- I have tried only Great barrier reef chromis (C.nitida) and they do live as a shoal until they mature, usually at 2"ish, then they fight to the death and you end up with one. I had WW3 in my tank for 2weeks and went from 10 to 1 and the one that was left died within a week because it was so damaged from fighting!
Just to add to the confusion there is another one, C. caerulea, which looks like 'green chromis' although I have never positively identified these in a LFS which doesn't mean they are not readily imported.
Confusion added to confusion, in May 2017 a new species Alelia’s Damselfish (Altrichthys alelia) was discovered- and guess what it looks just like a 'green chromis'.
So guys which species of green chromis do you have
@Chavin20- I have tried only Great barrier reef chromis (C.nitida) and they do live as a shoal until they mature, usually at 2"ish, then they fight to the death and you end up with one. I had WW3 in my tank for 2weeks and went from 10 to 1 and the one that was left died within a week because it was so damaged from fighting!
Haydn
Active Member
They are stunning fish but I wouldn't advise a group.
I have always thought they just have a relatively short life span. A group of 10 usually dwindles down over time, I think I’m down to 5 again, but I don’t see any significant aggression in my 180. I have 6 springerii damsels in there too and they all get along for the most part.
PatW
2500 Club Member
I had 3 small Chromis viridis, blue green chromis, and one quickly dispatched the other 2 in quarantine.
I then got 3 small Chromis cyaneus, blue Chromis from the Caribbean. They did fine. The large blue green Chromis will harass them. But I guess they all look alike to him because he seems unable to pick on the least dominant.
I then got 3 small Chromis cyaneus, blue Chromis from the Caribbean. They did fine. The large blue green Chromis will harass them. But I guess they all look alike to him because he seems unable to pick on the least dominant.
Juskr
Community Member
I had one Chromis (1.5 inch) and added 6 more that were about .75 inches each. After one week, I noticed one had been beaten up with the tail fin chewed up and completely gone. Before I could setup a hospital tank, the fish went missing. I didn't notice any aggression between the Chromis and have kept a close eye as I work from home and able to view the tank all day. I am wondering if my blue tang is responsible (blue tang did beat up a Kaudern's Cardinalfish by nipping the tail fin).
My tank is a 120 gallon (4x2x2) and I have been feeding heavily the first week. I will post an update after a week or two.
My tank is a 120 gallon (4x2x2) and I have been feeding heavily the first week. I will post an update after a week or two.
PatW
2500 Club Member
I have told that Chromis aggression tends to occur at night. I have noticed fish looking fine in the evening and beaten up the next morning. The only possible aggressor was a chromis.
Haydn
Active Member
May I ask how you identified them as C. viridis because in my experience when they are small C.viridis is virtually indistinguishable from C. atripectoralis. The only way I have found is to observe the fish in the dealers tanks for a period and check for aggressive behaviour and that isn't 100% accurate.
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