Fascinating Chromis Behavior

Gone Reefin’

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Fascinating and concerning. Here is the situation. Put 6 blue green chromis in QT a month ago. Went hypo to rule out some parasite intros. For the first 2 weeks, all was great. All fish adapted to hypo well, active and eating.

2 weeks in, I noted one fish hanging in the corner. No aggression noted, just hanging there and loss of appetite. After a week, this fish passed. I chalked up to a QT loss. Important to note, up until this death, the other 5 fish were active, eating well, and overall just looked great. Immediately after death, a new member of the 5 (not the smallest), immediately began a weak appetite and hanging in the same corner as the RIP fish. By the way, I know it is not the same fish that died as the sizing is larger. This fish remained this way for a week, and perished yesterday. Other 4 looking great during this time.

You know where this is heading. Yesterday, weak fish passed. Today, a member of the 4 is not eating and in the same corner! This is extremely interesting. I know this is a known phenomenon, but it almost appears that a new member becomes relegated to the culling immediately after previous passing. Like an understood pecking order. There is not aggression that I am witnessing. Food floats by the target fish and they could eat without hostility if they wanted. Just thought I would post this fascinating observation.

PS, starting to raise salinity now, so in a week these guys will be ready for display at which point I hope the cycle breaks.
 

edsbeaker

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Fascinating and concerning. Here is the situation. Put 6 blue green chromis in QT a month ago. Went hypo to rule out some parasite intros. For the first 2 weeks, all was great. All fish adapted to hypo well, active and eating.

2 weeks in, I noted one fish hanging in the corner. No aggression noted, just hanging there and loss of appetite. After a week, this fish passed. I chalked up to a QT loss. Important to note, up until this death, the other 5 fish were active, eating well, and overall just looked great. Immediately after death, a new member of the 5 (not the smallest), immediately began a weak appetite and hanging in the same corner as the RIP fish. By the way, I know it is not the same fish that died as the sizing is larger. This fish remained this way for a week, and perished yesterday. Other 4 looking great during this time.

You know where this is heading. Yesterday, weak fish passed. Today, a member of the 4 is not eating and in the same corner! This is extremely interesting. I know this is a known phenomenon, but it almost appears that a new member becomes relegated to the culling immediately after previous passing. Like an understood pecking order. There is not aggression that I am witnessing. Food floats by the target fish and they could eat without hostility if they wanted. Just thought I would post this fascinating observation.

PS, starting to raise salinity now, so in a week these guys will be ready for display at which point I hope the cycle breaks.
Just a guess on my part, but it seems that the highest in the hierarchy may be getting rid of them one by one. It could be by intimidation which causes them to try and get away, but has nowhere to hide, except to go into the corner. This stresses the fish to the point of not eating and dying.

Maybe turn your iPhone video on to see what’s going on while you are out of the room, but that would be my guess.
 
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fish_collector

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You've got 2 things going on.
First, chromis won't cohabitate like you think they will, they will almost always kill each other off one at a time.
Second, chromis are the #1 carrier of uronema and being in hyposalinity makes it much worse. Do/did any of the chromis have ANY signs of a red band or area on their body? Full strength seawater and copper would have been a better treatment for ich with chromis.

 

Freenow54

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Just a guess on my part, but it seems that the highest in the hierarchy may be getting rid of them one by one. It could be by intimidation which causes them to try and get away, but has nowhere to hide, except to go into the corner. This stresses the fish to the point of not eating and dying.

Maybe turn your iPhone video on to see what’s going on while you are out of the room, but that would be my guess.
I have seen animals do this. Its called worrying. I had a cat that loved killing. After a few baby birds and a rabbit died I tied it to a tree with all intent to feed it ect. A blue jay came in sat about 3 feet above it and started screeching and would not stop. The cat had its eyes closed , and paws over its ears and would have died if I had not let it off the leash
 
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Gone Reefin’

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KLC, I get what you are saying, totally. That is what is fascinating, no aggression, just one goes off to die. I’m guessing you’re not a believer of “schooling”, lol. I get it, that is an ocean behavior and is not easy in a glass box, but I’ve seen many examples of success reported on these forums. Sure, question is how many, tank size, etc, but no hard answers to these questions I have seen.

Also, no sign of uronema or red band. Fish eating, look great one day, next day they are banished to corner. Die about a week later. I do know that uro is a risk and hypo is reported to make it worse, but I treat all fish with hypo before my display. I have sand and rock in QT so copper is not an ideal option.
 

fish_collector

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It's not that I'm not a believer of schooling. With chromis, they'll eliminate one another one at a time, unless uronema gets them first.

I can go to any LFS who has a tank full of chromis and pick out several with uronema in the bunch, it is what it is.
 

lombeard

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It's not that I'm not a believer of schooling. With chromis, they'll eliminate one another one at a time, unless uronema gets them first.
I know it seems to happens a lot as there are countless threads on it but I've never had issues with Chromis in all of my tanks, no idea why - maybe it's just luck. I have 10 currently in my tank, they do bicker a fair bit but I haven't lose any of them to bullying and they're spawning constantly now so they're extra spicy. 🤣
 

MoeStachio

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This 100% sounds like we need to consult a fish psychologist lol

It's super odd they're all going to the same corner to die.

It does sound like intimidation and exile to me, so they're sent off to the corner of shame to die alone. But I'm no expert
 

lombeard

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It does sound like intimidation and exile to me, so they're sent off to the corner of shame to die alone.
Survivor Immunity GIF
 

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