Are there actually any Friendly Damsels? Yes there are .. the related Chromis

[albertthiel]

Very interesting article on Chromis species,and other of the same and related genera


http://www.reefkeeping.com/issues/2003-11/hcs3/


Albert

[az]

chromis may not be as bad to all other fish like damsels but they do kill each other a lot.

[albertthiel]

chromis may not be as bad to all other fish like damsels but they do kill each other a lot.

The Green Blue one is the safest IME ... Chromis viridis ... usually keep them in odd numbers like 3 or 5 ... and in say a 30 gallon tank with non aggressive fish and you should be ok

Albert

[az]

The Green Blue one is the safest IME ... Chromis viridis ... usually keep them in odd numbers like 3 or 5 ... and in say a 30 gallon tank with non aggressive fish and you should be ok

Albert

thats what we used to advise people about the green/blue but this is what they told us later;

started with 7 ended with 3, started with 5 ended with 2, started with 3 ended with 1, started with 15 ended with 6....and so on.

they actually behave better when there is some other aggressive fish in the tank, xxxx scared they start schooling needing each other for cover, but when they are not scared they start killing each other one by one.

[albertthiel]

thats what we used to advise people about the green/blue but this is what they told us later;

started with 7 ended with 3, started with 5 ended with 2, started with 3 ended with 1, started with 15 ended with 6....and so on.

they actually behave better when there is some other aggressive fish in the tank, xxxx scared they start schooling needing each other for cover, but when they are not scared they start killing each other one by one.

Not my experience but I do thank you for sharing it for the benefit of other readers

[Greatwhite]

I've never had a problem with chromis killing each other.. I've usually kept 5 at a time.. I DID have a problem with them jumping out though.  Perhaps it was murder, but the crime scene was always tainted by dogs before my CSI Fish group could get in for the investigation.

[JetJumper]

I have had similar experience to what AZ said and I am aware of someone else as well who has a 210G tank that most of them killed each other off. 

[albertthiel]

I have had similar experience to what AZ said and I am aware of someone else as well who has a 210G tank that most of them killed each other off. 

Thank you all for your input and it looks like we have 3 scenarios going on right now :

- they kill each other
- they disappear for some reason
- they jump and carpet surf and side

Each of those could indeed happen IMO ... it may depend on the tank and what else is in it and what its size is vs how many Chromis viridis are in the tanks'

just trying to recap ...

[Stussi613]

I posted on the Facebook group that I have also heard they will thin the herd out eventually as well.  I know a few people who have had the same experience of them eventually turning on each other.

I wonder if the theory of them needing to feel fearful and sticking together for protection holds true.

[JetJumper]

- they kill each other
- they disappear for some reason
- they jump and carpet surf and side

These are all related in my opinion

If Fish A scares the poop out of Fish B and Fish B swims to get away and goes up and out of the tank.. Thats essentially killing the other one

I have seen personally that when I had 5 chromis one would hide in the rocks and not move EVER.. he was scared of the other chromis.  This caused him not to eat.. and die.

[Greatwhite]

I think that the point is that the Chromis are GENERALLY friendly to the other tank inhabitants if kept in a small school... Sometimes they may be cranky at each other though.

[albertthiel]

I think that the point is that the Chromis are GENERALLY friendly to the other tank inhabitants if kept in a small school... Sometimes they may be cranky at each other though.

Yes that is a good way of putting it indeed

Albert

[Herstead]

What I have read is that they are less likely to kill other species of chromis if kept together. So you could keep a blue green with a blue reef and a yellow chromis w/o trouble.

Does anyone here have experience with this? I want to know because then I might try a mixed group.

- Jonathan

[albertthiel]

What I have read is that they are less likely to kill other species of chromis if kept together. So you could keep a blue green with a blue reef and a yellow chromis w/o trouble.

Does anyone here have experience with this? I want to know because then I might try a mixed group.

- Jonathan

I have seem reports of such a mix going both ways ... so let's see what others have to contribute if they have kept several species together, and what their experiences were.

IME though you can keep the blue/green ones in a group, in a sufficiently large enough tank, and in 99% of all cases everything will be fine, but as you know, in this bobby there are always exceptions, so at times, I have to agree, there will be infighting.

One point that I did not mention is that if you keep a group of them, they should all be introduced "at the same time", and as most posts/articles will tell you, they should be kept in odd numbers.

The exact reason for the "odd numbers" is not totally clear though, but that is the recommendation found most of the time to avoid issues with conspecific aggression.

Hopefully other readers will contribute to this  thread.

Albert

[Canoe]

I have a pair of clowns in a 48G bowfront. Added 9 very small blue/green chromis. They seemed to thrive, liking the upper water column. After a few weeks of the clowns being scardy-cats, the clowns seemed encouraged to leave their rocks and explore the upper waters. I had two auto feeders, one with crushed small pellets and the other with flake, so with the feeder outputs set very small, the tank was fed a tiny amount eight times a day. Everything seemed fine, apart from the female clown deciding to take the feather-duster apart.

The chromis grew quickly. Later, at night they'd hide from a spontaneous purchase big-eyed black-barred soldier fish, which was keeping them exercised during the day. This soldier fish had to go as it was obviously too strong of a swimmer to be happy once it grew (went to Big Al's former shark tank; it's huge now!). Some weeks after the soldier fish was removed, the chromis started disappearing, one at a time, around every three weeks. I'd got in the habit of counting them due to the soldier fish's antics, watching as they'd regroup from their various night's hiding places. One to two days after the count was off by one, the tank got meaningful skimmer output for two days, which was a dramatic signal as it was usually sparse except when I vodka dosed. Water params did not spike... Never found a body, not in the tank nor on the floor. Barebottom tank, rock was dead rock that was cultured from a bottle, so there shouldn't be any worms to remove remains? Never saw the hermits change their foraging behavior. I observed the chromis decline in numbers, but have no evidence of the cause or where they went, other than a very temporary increase in skimmer foam output.

I'd love to have that 'school' back, but without knowing they can thrive...

[albertthiel]

I have a pair of clowns in a 48G bowfront. Added 9 very small blue/green chromis. They seemed to thrive, liking the upper water column. After a few weeks of the clowns being scardy-cats, the clowns seemed encouraged to leave their rocks and explore the upper waters. I had two auto feeders, one with crushed small pellets and the other with flake, so with the feeder outputs set very small, the tank was fed a tiny amount eight times a day. Everything seemed fine, apart from the female clown deciding to take the feather-duster apart.

The chromis grew quickly. Later, at night they'd hide from a spontaneous purchase big-eyed black-barred soldier fish, which was keeping them exercised during the day. This soldier fish had to go as it was obviously too strong of a swimmer to be happy once it grew (went to Big Al's former shark tank; it's huge now!). Some weeks after the soldier fish was removed, the chromis started disappearing, one at a time, around every three weeks. I'd got in the habit of counting them due to the soldier fish's antics, watching as they'd regroup from their various night's hiding places. One to two days after the count was off by one, the tank got meaningful skimmer output for two days, which was a dramatic signal as it was usually sparse except when I vodka dosed. Water params did not spike... Never found a body, not in the tank nor on the floor. Barebottom tank, rock was dead rock that was cultured from a bottle, so there shouldn't be any worms to remove remains? Never saw the hermits change their foraging behavior. I observed the chromis decline in numbers, but have no evidence of the cause or where they went, other than a very temporary increase in skimmer foam output.

I'd love to have that 'school' back, but without knowing they can thrive...

Have you checked for any crabs in the tank that may only come out at night ...

Did you see the Chromis fighting with each other ? That would happen during the day ...

I have a feeling but cannot be sure that there is something else going on in that tank ...

Just saying

[Darth]

I personally bought  7 blue/green chromis about a year ago, maybe more, they were all the same size, today I have 6 left and you can see the hierarchy amongst them as the size is big to small, they get a little bigger as you compare each one, yet they were bought at the same time and same size, they are not aggressive towards each other until feeding and then it is just who gets it first. So my long winded post is started with 7 now at 6, I think I lost the 7th because of natural causes in the tank (aka being the runt or was sick) but over a year later no issues

[albertthiel]

I personally bought  7 blue/green chromis about a year ago, maybe more, they were all the same size, today I have 6 left and you can see the hierarchy amongst them as the size is big to small, they get a little bigger as you compare each one, yet they were bought at the same time and same size, they are not aggressive towards each other until feeding and then it is just who gets it first. So my long winded post is started with 7 now at 6, I think I lost the 7th because of natural causes in the tank (aka being the runt or was sick) but over a year later no issues

Thanks for sharing your experience and yes that hierarchy does eventually come about and I glad to read that you did not notice any infighting, rather that the one you lost may have been to other causes. that is also what has been my experience, but ... all need to be introduced at the same time and all need to come from the same tank at the dealer where they have been living / swimming together for some time.

Of course, there will always be exceptions but the norm is that many can indeed be kept in the same tank without any issues IME

Albert

[Canoe]

Have you checked for any crabs in the tank that may only come out at night ...
Did you see the Chromis fighting with each other ? That would happen during the day ...
I have a feeling but cannot be sure that there is something else going on in that tank ...
Just saying

I too had the feeling that something else was going on, but I never saw anything and I can't figure out what it could be.

The canister filters were out of commission and dry for half a year, then cleaned and soaked in bleach, and then many many rinses with water, then with RO/DI. The rock in the canister filters was synthetic rock, purchased new, as was the pad media. The live rock in the tank was a mix of rock taken from Florida over 25 years ago (sitting dry as ornaments since then), and dry rock taken from a system decommissioned for over a year. The tank was cleaned like the canisters and is barebottom, so no sand taken from anywhere. I cycled it with the bacteria-in-a-bottle from the LFS. I had a small HOB skimmer to start with, then replaced it with a HOB Deltec. Both skimmers where used and got the same treatment as the canister filters.

The soldier fish had been trying its best to catch them, trying to single one out from the "school", but it always failed. I saw regular half-hearted short-lived chases between the chromis, but rarely contact, and never when feeding. Once the soldier fish was removed, the frequency of this increased but was not the dominant behavior, although there was one smaller chromis that the largest chromis seemed to regularly chase to the far side of the school. I never saw damage.  They continued their morning reunion and "schooling", anxiously seeking each other out.

Along with the soldier fish, I got a small Clarkii, which I figured its colour would be different enough from my pair of Ocellaris. It was tolerated for weeks, then the female Ocellaris started nipping and one day after around a week it went postal and shredded or removed 90% of the fins of the Clarkii. Shortly after that, the female Ocellaris ripped the feather-duster apart. In a separate tank on top but with the water flow, the Clarkii actually regrew all its fins, looked great, and the LFS took it to find it a home.

There are small hermits in the tank. They were aggressive with each other until I put a supply of larger shells into the tank. I never saw them gather together as though on a carcass.

When I decommissioned the large canister filter (3e), I was surprised to find a short fat worm in the top, maybe two inches long.

With the rock dry for so long, the usual suspect for hitch-hikers isn't viable?
Possibly from the hermits, in/on the fish, frogspawn, pulsing xenia, feather-duster, or in the trace water than was transferred with those. But I do note that one worm of unknown pedigree.

[albertthiel]

I too had the feeling that something else was going on, but I never saw anything and I can't figure out what it could be.

The canister filters were out of commission and dry for half a year, then cleaned and soaked in bleach, and then many many rinses with water, then with RO/DI. The rock in the canister filters was synthetic rock, purchased new, as was the pad media. The live rock in the tank was a mix of rock taken from Florida over 25 years ago (sitting dry as ornaments since then), and dry rock taken from a system decommissioned for over a year. The tank was cleaned like the canisters and is barebottom, so no sand taken from anywhere. I cycled it with the bacteria-in-a-bottle from the LFS. I had a small HOB skimmer to start with, then replaced it with a HOB Deltec. Both skimmers where used and got the same treatment as the canister filters.

The soldier fish had been trying its best to catch them, trying to single one out from the "school", but it always failed. I saw regular half-hearted short-lived chases between the chromis, but rarely contact, and never when feeding. Once the soldier fish was removed, the frequency of this increased but was not the dominant behavior, although there was one smaller chromis that the largest chromis seemed to regularly chase to the far side of the school. I never saw damage.  They continued their morning reunion and "schooling", anxiously seeking each other out.

Along with the soldier fish, I got a small Clarkii, which I figured its colour would be different enough from my pair of Ocellaris. It was tolerated for weeks, then the female Ocellaris started nipping and one day after around a week it went postal and shredded or removed 90% of the fins of the Clarkii. Shortly after that, the female Ocellaris ripped the feather-duster apart. In a separate tank on top but with the water flow, the Clarkii actually regrew all its fins, looked great, and the LFS took it to find it a home.

There are small hermits in the tank. They were aggressive with each other until I put a supply of larger shells into the tank. I never saw them gather together as though on a carcass.

When I decommissioned the large canister filter (3e), I was surprised to find a short fat worm in the top, maybe two inches long.

With the rock dry for so long, the usual suspect for hitch-hikers isn't viable?
Possibly from the hermits, in/on the fish, frogspawn, pulsing xenia, feather-duster, or in the trace water than was transferred with those. But I do note that one worm of unknown pedigree.

Thank you for the description, very methodical indeed, of all the things you did and looked at yet found nothing that would have  caused what ahas  going on. Well actually I think your soldier fish was keeping things in check and sort of running the show and so all others kind of submitted and no territorial fights or activity was going on.

However when that Clarkii clown was introduced, and the Soldier fish gone, the other Clown decided that it was time to show who the boss was, so to speak, and that is when gradually it starting attacking the Clarkii Clown more and more, as you noticed ...

Clowns are very territorial and the Ocellaris are certainly some of the most, except maybe for the Maroon Clown (Premnas sp.). The Clarkii clowns are usually not that territorial and so the Ocellaris would have had fair game (well unfair really).

One the internal status quo is disturbed, the real nature of some of the fish will come out and they will tend to become the dominant ones and that is what I think happened in your tank.

Glad you removed the Clarkii and placed it in another home so it could recoup from getting beaten up  ...

It just goes to show that even making one change in a tank can upset things completely.

Glad you figured most of it out though

Albert