Are New Fish More Prone to Die?

[Julles]

I'm wondering, because this has happened to me several times now, and it just happened again today.... The two koi I had bought on June 3 both came up dead this evening.

These were not tiny fish - one was about 5" and the other about 7".

The larger one, since I've had him, I've only glimpsed him once or twice, but he seemed to be getting along with the others, hanging out at the waterfall as they like to do.

The smaller one, I didn't see him too much, either, but I did see him a bit more frequently.

Neither one seemed to have "schooled" with the other fish.

Could it be the established fish ostracize the new fish, and perhaps stress eventually kills them?  And why would they both die on the same day, at about the same time - with no marks on either one?

[Julles]

PS:  The shebunkin I bought the same day appears to be fine and swimming along with the other goldfish.  (Hard to tell, 'cause they all look so alike.)

The larger koi who died was orange / red with black spots on his back - a rare color, and I had felt thrilled to have found and bought him.    :'( 

[frloplady]

Do you quarantine your fish?  I can think of a few scenarios..one being that your fish in the pond are KHV survivors..but also carriers and it kills new/incoming fish.  That would be what I would HOPE is NOT the case.  That would not affect goldfish.

Other scenario is that your fish have a parasite that is under control for THEM, but that the new fish are not acclimated to.  One of the things that needs to be done with the quarantine procedure is to bring in one fish from the pond with the new guys to "exchange" bugs with.

That said small koi are always more suseptible to croaking as they are a bit more fragile..they are babies! 

[Mikey]

In the Spring I purchased a koi and a couple of wakin and shubunkin.  My local fishmonger was concerned and warned me that since I had not added any new fish to my pond in some ten years that I might loose fish.  Even though his fish were healthy and my fish were healthy they may each be carrying viruses that the other fish may not be able to adapt to.  No amount of quarrantining would help.

I guess the best way to explain it is to use the anology of what happened to the American Indians when Europeans came here.  We introduced them to bugs that they did not have resistance or anti-bodies to overcome.  Many died.

It's now been about three months since I introduced these fish.  No, I didn't quarrantine.  My fish monger has some VERY expensive koi is quite careful about keeping his fish clean.  I lost the newly introduced koi last week.  The other fish seem okay.........so far.

I didn't ask my fish supplier this question, but I would imagine that if I introduced a new fish to my pond every couple of years I would be better off than only doing it every decade....

I hope this make sense to you......

 

[barb]

How sad, I'm so sorry your new fish didn't make it. 

[miguynmkoi]

Julles I'm sorry about your new fish.  I'm glad you brought up this question.  I experienced this problem too even when I quarantined.  Frloplady and Mikey you've made some sense of all the hoops we go thru and have it all dashed. 

[LeeAnne151]

Depending on where you purchased the new fish, they could have been stressed or diseased at that location too.

Especially if you "rescue" them from Wal*Mart, PetSmart or other places not owned and staffed by experts.

All in all, Yes, new fish are more prone to die.

[frloplady]

Not quarantining fish and it doesn't matter where they are from is dangerous.  Especially to your existing fish.  KHV is out there in Koi.  Ask the many hobbiests that have lost their entire collections.  The dealers that were wiped out..along with many of their customers.  One here in our state had that exactly happen.  Family operation that was just getting going.

It's great that your dealer is careful with his fish, but please be careful with yours.  A quarantine tank gives the opportunity to treat for parasites, scrape and scope to see if there is bugz, and heat cycle to catch KHV before it gets to your pond.  Then bring in a canary fish from the pond and see how the 2 sets of bugs mingle.  It could have been your 10+ year old collection that died and the new fish lived.  Just please be careful!!

In the Spring I purchased a koi and a couple of wakin and shubunkin.  My local fishmonger was concerned and warned me that since I had not added any new fish to my pond in some ten years that I might loose fish.  Even though his fish were healthy and my fish were healthy they may each be carrying viruses that the other fish may not be able to adapt to.  No amount of quarrantining would help.

I guess the best way to explain it is to use the anology of what happened to the American Indians when Europeans came here.  We introduced them to bugs that they did not have resistance or anti-bodies to overcome.  Many died.

It's now been about three months since I introduced these fish.  No, I didn't quarrantine.  My fish monger has some VERY expensive koi is quite careful about keeping his fish clean.  I lost the newly introduced koi last week.  The other fish seem okay.........so far.

I didn't ask my fish supplier this question, but I would imagine that if I introduced a new fish to my pond every couple of years I would be better off than only doing it every decade....

I hope this make sense to you......

 

[Julles]

Wow, thank you for your answers!  I am sure this is the problem.... not KHV (I just Googled and got myself an education!), but the particular bacteria that live in my pond, which my "old" fish are used to, but the new ones can't endure more than a week or two.

I don't know that I'd have a way to set up such a quarantine tank, so perhaps I'll have to give up the hope of buying an orange-w/black-speckles koi.  But I'd rather have ALL my "old" fish, than risk loosing some because I brought home something new.

[frloplady]

Julles a quaratine tank for smaller fish doesn't have to be huge.  A 100 gallon stock tank properly set up would work great.  DIY filter can be made to filter it.  I  have a 300 gallon that we set up with DIY bottom drains with a DIY upflow barrel filter.  I have a couple of filter that I will use to exchange material for new tanks to help seed the filter.  Household ammonia can be used to help feed a new filter before the fish even arrives.  Give it a goldie buddy from the main pond.

With the tank you have a close up view all the time of the new fish and can keep an eye on it to see if it needs treatment for parasites or whatever.  A 300 watt aquarium heater can be used to heat cycle for KHV if you want to keep safer from that too.

Mary