Cpd's/galaxy Rasbora Killed The Others

[markanthany]

Hey all,
 
So as the title says, we woke up to a tank of five CPD's with one alive and the other four dead.  I feel bad because this is our first time keeping them and we got them anyway even though quite a few were dead in the tank from which they were purchased.  However, everything in the tank appeared to be healthy so I didn't think twice (and we had been looking for them for quite a while.)  After about 12 hours of having them home, we woke up to four dead in the tank with nipped fins and bleeding sides with one still happily swimming in the tank.  We checked the tank parameters and they are as follows: 5g, 69 degrees F, neutral-slightly acidic PH, ammonia and nitrates and nitrites 0.  The tank only has a small amazon sword with some sizeable rocks, so my initial thought was aggression from not enough hides, we just didn't expect it to be an issue so quickly.
 
However, I looked up how to sex them, and we found that the one surviving is indeed male, with the other four being female.  What gives?  I figured if anything, 1 male to 4 female ratio would be fine and possibly ideal for breeding.  Why would one male of any species kill off all the females?  Were lack of enough hides/plants really the cause?  Or something else?
 
The tank from which they were purchased at the store had about the same amount of hides/cover but a 5g with many more CPD's in it.  Though there were about 10 alive, there were about 5 or more dead at the bottom.  No idea if they were wild caught or captive bred.

 

[Ch4rlie]

Hello, welcome to the forum.
 
Right, a few questions first.
 
Is this tank cycled?
If unsure, have a read of this - Cycling Your New Fresh Water Tank
 
This is my first suspicion as nipped fins could be mistaken for rotting fins and bleeding gills could simply be red gills which is a classic syptom of ammonia poisoning. But this alone is not enough for me to determine if this is actually the case due to the simple fact you bought these fish from a LFS presumably, with dead fish in the same tank in which they were being kept, this alone rings warning bells in mind.
 
First will need to know a few things, as already mentioned is the tank cycled?
What kind of test kit are you using (dip strip kind or a liquid based test kit?
What other tank stocking do you have in this tank?
How long has this tank been running?
Do you use dechlorintaor when adding fresh water from the tap?
 
Some of these questions are pretty basic but need to ask to get a better picture of how this tank runs and what is happening.
 
And lastly, a 5 gallon tank is not really recommended from me for these beautiful active little danios. I keep a nice little shoal of 16 CPD's in a 20 gallon long tank (3 ft long), they share this tank with a small shoal of 10 harleqiuins (espei), red cherry, pinocchio and amano shrimps with would say moderately planted set up ( see my sig pic) and have not had any real issues between them to date from over a year since I started keeping these.

 

[markanthany]

Hello, welcome to the forum.
 
Right, a few questions first.
 
Is this tank cycled?
If unsure, have a read of this - Cycling Your New Fresh Water Tank
 
This is my first suspicion as nipped fins could be mistaken for rotting fins and bleeding gills could simply be red gills which is a classic syptom of ammonia poisoning. But this alone is not enough for me to determine if this is actually the case due to the simple fact you bought these fish from a LFS presumably, with dead fish in the same tank in which they were being kept, this alone rings warning bells in mind.
 
First will need to know a few things, as already mentioned is the tank cycled?
What kind of test kit are you using (dip strip kind or a liquid based test kit?
What other tank stocking do you have in this tank?
How long has this tank been running?
Do you use dechlorintaor when adding fresh water from the tap?
 
Some of these questions are pretty basic but need to ask to get a better picture of how this tank runs and what is happening.
 
And lastly, a 5 gallon tank is not really recommended from me for these beautiful active little danios. I keep a nice little shoal of 16 CPD's in a 20 gallon long tank (3 ft long), they share this tank with a small shoal of 10 harleqiuins (espei), red cherry, pinocchio and amano shrimps with would say moderately planted set up ( see my sig pic) and have not had any real issues between them to date from over a year since I started keeping these.

 
Hi, thank you for your response!
 
The tank had been running for about two weeks with start up bacteria, plants, and a small filter.  We used strip test and liquid test for ammonia, all readings came out perfect or preferable, PH was a little on the alkaline side.  We were actually able to return to the LFS today and exchange the for a store credit, to which one of the employees keeps about 50+ CPD's in a large tank.  He was shocked when he brought him the dead fish which were nearly dismembered (chunks missing, spine ruptured, no fins, bloody scratches, etc.) and he also tested our water sample and confirmed that they were definitely killed by the other CPD.  He did say though that he had never heard of this happening, and while I thought I had previously sexed them correctly according to the internet (thinking that the females have lighter bellies) the employee at the LFS told me that he tried sexing his that way, but what he thought were all females turned out to be males, and that what we had purchased were still to small to properly sex.
 
In short, the employee concluded that it was a freak accident, and that they don't typically behave this way though he had been keeping males and females in several differently sized groups and tanks just fine.  He said the five in a five gallon was fine, but I agree with you that they would enjoy more space than that as they seem very energetic.
 
For anyone else though that may have this problem in the future, I lost the link to it but I did find a page that said that groups of male CPD's can become aggressive and fight until only one is left, and I'm guessing that that is what happened to us, seeing as the biggest of the group is the only one left alive.  That was really all I was able to find out about it.

 

[the_lock_man]

The dead fish would have been pecked at by the live one(s) anyway, so that's not really any evidence. 
 
The LFS guy would not want to admit that he'd recommended a poor set up, my personal opinion matches that of Ch4rlie - a 5gallon is too small for CPDs.
 
I would suggest that your return the 5gallon, buy the biggest size tank that you can afford and fit in the space available, and the cycle it fishlessly, using the instructions we have in our Cycle Your Tank section. I recommend the biggest tank, because the bigger the tank, the easier it is to keep stable.

 

[markanthany]

The dead fish would have been pecked at by the live one(s) anyway, so that's not really any evidence. 
 
The LFS guy would not want to admit that he'd recommended a poor set up, my personal opinion matches that of Ch4rlie - a 5gallon is too small for CPDs.
 
I would suggest that your return the 5gallon, buy the biggest size tank that you can afford and fit in the space available, and the cycle it fishlessly, using the instructions we have in our Cycle Your Tank section. I recommend the biggest tank, because the bigger the tank, the easier it is to keep stable.

 
Sorry, I failed to mention that when we found them dead in the tank, one was still partially alive (the one with the visible bloody marks) and being attacked by the remaining CPD.  That's what lead us to think he had killed them all while we had slept.
 
We have a 60g actually that's still waiting to be set up.  We could wait until after it's cycled and then try them again, though I'm a little nervous now.
 
This morning I found the last one dead in the tank, floating at the surface.  He doesn't have nipped/torn fins, bloody gills or anything, just simply dead.  (Ammonia and nitrate were extremely low-zero with little nitrate.  I don't remember what the water hardness was.)
 
Are these fish just very fragile?  Do you think he was stressed being by himself or maybe the water parameters that I posted were still poor?  Or just stress in general?  Internal parasites maybe? The only thing I can figure is that either one, it was too alkaline (7.8) though I read that they were fine in more alkaline water, or two, they were a batch of wild caught CPD's.  When I asked the employee at the LFS, he didn't know if they were wild caught or not.  The only thing I can think of now from what I've managed to find online on CPD's is that the wild caught don't do very well and stress very easily.
 
They happen to be my significant other's favorite fish though, so I would really like to try them again but obviously in a larger tank.  Does anyone have anymore information on this species?  I've been crawling the internet for more information on them but it's a bit hard to find, with most of it contradicting itself.  
 
Thanks again to everyone who's posted.

 

[Ch4rlie]

More info on CPD's for you - Celestichthys margaritatus / Celestial Pearl 'Danio'
 
I kind of doubt if the other CPD's killed their own kind, its possbile but unlikely imho as I find them a peaceful social fish with little agression. Though its pretty certain likely they snacked on their dead tankmates when they passed away, this is common with most species of fish.
 
I still have a feeling your cpd deaths are likely due to the LFS tank setup, 50 plus in one little tank is going to stress out these little guys and stress leads to lowered immune systems which inevitably lets diseases in.
 
2 weeks is not really much in term in cycling your tank, though it may be the case when you added start up bacteria, this largely depends on what brand you used, a lot of brands are useless to be honest.
 
Do you have any other fish in this tank btw?
 
And if you happen find that link about male cpds attacking others until there is only one, posting that would be useful to read, not something I have heard of in CPD's actualy.

 

[Gruntle]

I was seriously considering these for my tank until I found I cannot get them in Australia unless I spend an absolute fortune.
 
My research took me to http/www.seriouslyfish.com/species/celestichthys-margaritatus/ and I was surprised by their comment "Buy as many as possible, ideally 20 or more, as when larger numbers are present the aggression is spread between individuals" - I thought they were a peaceful fish.
 
I'm thinking that the fish may have died for other reasons as well, not fighting to the death. From what I know, they're a shy fish that will defend their territory, but I doubt they would kill each other. Not that I have any experience, to get a group of 20, I'm looking at nearly $400!

 

[markanthany]

More info on CPD's for you - Celestichthys margaritatus / Celestial Pearl 'Danio'
 
I kind of doubt if the other CPD's killed their own kind, its possbile but unlikely imho as I find them a peaceful social fish with little agression. Though its pretty certain likely they snacked on their dead tankmates when they passed away, this is common with most species of fish.
 
I still have a feeling your cpd deaths are likely due to the LFS tank setup, 50 plus in one little tank is going to stress out these little guys and stress leads to lowered immune systems which inevitably lets diseases in.
 
2 weeks is not really much in term in cycling your tank, though it may be the case when you added start up bacteria, this largely depends on what brand you used, a lot of brands are useless to be honest.
 
Do you have any other fish in this tank btw?
 
And if you happen find that link about male cpds attacking others until there is only one, posting that would be useful to read, not something I have heard of in CPD's actualy.

 
Sorry, I didn't explain the LFS's employees set up correctly.  What I meant to explain was that the LFS employee said he kept around 50 at home in a community 150g tank.  The actual store had about 10+ in a 10g.  
 
I know it contradicts many articles, though not all, that CPD's are not aggressive, but I promise you that this particular batch were.  When we woke up, we found 3 out of 5 dead, with one partially dead.  The largest in the tank and the last to survive, was going nuts to kill the one that wasn't dead yet, which also had bloodied marks on its sides.  Then when we returned to the LFS the next day there were only two CPD's left in their tank, and the larger was chasing and nipping at the smaller one the entire time.  I have no idea why, but that is what we experienced.  I'm not saying that other factors couldn't have contributed to their death because I'm sure there were, but I am certain that these CPD's were particularly aggressive.
 
I'm still not sure why the other died.  Unless you are correct in the start up bacteria that we used being useless, I really have no idea.  I'll have to do more research into startup bacteria and purchase a better one for future use.  As to your other questions, the CPD's were the only thing in the tank aside from two ghost shrimp, the ghost shrimp are fine.  The way in which we set up this tank was also the same in which we've set up our other five 5 gallons; brand new tanks with dechlorinated tap water, two inches of sand, start up bacteria, and a few peace lilies and some other plants to comprise about 1/4th-1/3rd of the tank along with some rocks.  We let that sit for at least two weeks and usually add ghost shrimp and corys to help with clean up when we decide to add fish.  All other tanks have great readings and happy, healthy fish.  We also did not add any fertilizer or any kind of chemical to the tank.
 
 
The only thing I can think of that I don't believe our test kits included was a reading for water hardness.  It just baffles me a bit (outside of the aggression from the CPD's we bought) what it could be that possibly threw off the water chemistry to kill the last one?  Other than, I can only think that it possibly died from stress from maybe being alone, or the layout of the tank somehow  (had plenty of hiding space in the plants) or perhaps they were wild caught and just did not acclimate to the change from the LFS tank to our tank well.
 
 
Gruntle:  Wow, that is a lot of money for CPD's.  Ours were only $5 a piece, so we obviously wanted to snatch them up but I still feel terrible that they died.  It also makes me wonder why there were so many dead ones in the LFS tank as well.  Is it possible for fish to get some kind of parasitic or bacteria infection that makes them stress or become aggressive?  As for aggression though, from what I have read from few people that have had our same problem, the number of CPD's in a group vs the size of your tank is really important with mitigating aggression, and also possibly male to female ratio.  Like I said, I thought we had four females and one male, but an article I read said that if kept in too large of numbers compared to the size of the tank, the male CPD's will fight it out to the death until one is remaining, and I suppose that's what happened to us.
 
 
**I can't find the one particular article that I read earlier, but here is a thread of someone else with a killer CPD: http/www.aquaticquotient.com/forum/showthread.php/104449-Need-Help-My-Celestail-Pearl-Danio-Attack-Other-CPD-I-am-Lost
 
The more threads like this I find, the more I'm beginning to think that these 'one of a kind CPD's' aren't so.  I wonder what it is causing the aggression problems?

 

[Ch4rlie]

Ah, I understand now after re-reading your previous comments abou lfs numbers of cpd in tank, I misunderstood, sorry about that.

Hmm, well, don't think I can add much to that until I find a study or research into cpd behaviour on aggression. Will certainly not rule it out, would be most interesting if further information about these beautiful little fish.

Chalk it up to bad luck either way.

One thing springs to mind when you mentioned ghost shrimps. These can be mixed up with young macrobachium which looks incredibly like ghost shrimps. These macros are pretty predatory creatures that will snack on other small shrimps and small fish just like cpd's.

The easiest way to tell ghosts from macros apart is that macros have a pair of very long forearms with pincers. And macro if looked after grow huge as adults, pretty much lobster sized really

Gruntle - wow that's a small fortune for 20 of these cpd's, $400 Aus

 

[markanthany]

Ah,Ii understand now after re-reading your previous comments abou lfs numbers of cpd in tank, I misunderstood, sorry about that.

Hmm, well, don't think I can add much to that until I find a study or research into cpd behaviour on aggression. Will certainly not rule it out, would be most interesting if further information about these beautiful little fish.

Chalk it up to bad luck either way.

One thing springs to mind when you mentioned ghost shrimps. These can be mixed up with young macrobachium which looks incredibly like ghost shrimps. These macros are pretty predatory creatures that will snack on other small shrimps and small fish just like cpd's.

The easiest way to tell ghosts from macros apart is that macros have a pair of very long forearms with pincers. And macro if looked after grow huge as adults, pretty much lobster sized really

Gruntle - wow that's a small fortune for 20 of these cpd's, $400 Aus

 
Hooooooly shocker!!  I just looked up a few pictures of machrobachium and now I will be inspecting every 'ghost shrimp' extremely carefully.  That's scary!  
 
None with pincers in the former CPD tank, though.  Hmm.
 
And yes, I would really like to see that study.  So far all I can find on CPD aggression are articles on territorial behavior in males and threads of people having similar bad luck.  I'm thinking that once we move the baby musks out of our 10 gallon, we may try a few in there, and if they do well, maybe move them to the 60, but I'd be extremely hesitant to get them from the same LFS if they get their next order of CPD's from the same dealer.  I really feel like wild caught might be the culprit, or something to do with how they are housed maybe being the cause as to why they become territorial.  

 

[DoubleDutch]

I can tell you one thing : CPD's don't kill. Not other CPD's nor other fish !!
 
Kept them and bred them. Noticed two things:
 
- They show different behaviour in a species-only tank than in a cummunitytank. In the first they are a bit skittish in a shoal. In a communitytank they are brave, females have their öwn" plant they live around and males swim between those !
- CPD's after a while show unexplained issues after some time. Some get thin, have unexplained spots, some bloat aso. My suspecion is a viral infection like DGD (Iridovirus). Lost of people encounter the same issues (My son in Germany did as
  well). I quit keeping them cause of this.
 
In this case I'd say : Nitrite-spike is culprit.

 

[Demeter32]

Rarely do shoaling species kill their own kind, and the only cases I can think of is when the tank is too small and there isn't a proper number if fish to be considered a school. I've seen my sister's white skirts attacking each other because she had only one in those rather ridiculous "glow-light" cubes and added two new ones. The previous fish killed off the two new ones rather quickly, and it's still alive today, forever alone in that stupid 1gal cube...

But, I don't think that's really what happened here. New tank, which may or may not of been completely cycled, and adding already sickly fish (seeing as you said some were already dead in the tank) could of very well been the cause. This is even more likely if the fish were recently shipped to the pet store. They might of been already stressed from the shipping ordeal and then being moved again to a new tank didn't help. You should always choose fish from a tank that doesn't have sickly or dead fish in it. I would ask the employee how long the fish have been in their tanks. Any number of days under a week is iffy in my opinion.