Established neons wiped out by addition of new neons

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georgieooom

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Had 6 neons in my tank for about a year. last week introduced 6 new neons from Petco. I acclimated them temperature and ph wise. Slowly ovr the next few days all 12 neons are dead. Did not effect the zebra fish at all. A mystery I am looking to solve. Lots of plants in my 30 gal tank. This particular tank (my only one) has been up and running now since 1998. I'll post a picture some other time.
 
Were these the first fish you have introduced for a while? How many fish do you have in your 30g?
 
More than likely the new additions were already sick and carried some thing in. Sadly, most of us have had to learn the hard way about "Quarantining".

I "Quarantine" anything including plants and hardscape at least 2-4 weeks and monitor before they enter my existing tanks.
And yes some keepers have been lucky and have not had a problem, but... it's a roll of the dice IMO.
Your issue is a perfect example...
Good Luck!
 
Last edited:
need pictures of the fish

you introduced sick fish, which is why people should be quarantining new fish for at least 2 (preferably 4) weeks before adding them to a display tank.
 
Were these the first fish you have introduced for a while? How many fish do you have in your 30g?
I like having lots of plants in my tank. Good for oxygen in water & good for fish to have places to hide. Also gets rid of nitrogen so I don't have to change water. I had 6 zebra & 6 neon. Now I have 9 zebra & no neon.
Thanks for the inquiry!
Tank.jpg
 
I agree, the new neons carried something. This could have been an internal protozoan. Back some 10 years ago I had the same thing happen, except in my case whatever was introduced was killing all fish in the tank. It was an internal protozoan. There are no outward signs until the fish dies, behaving normal until that point. A necropsy by a biologist might determine the protozoan, but it really makes no difference because there are several (according to the biologist I consulted at the time) and by the time you isolate the species the fish will all be dead. Quarantining for several weeks is the only action to avoid this, I learned the hard way.

This comment...
Also gets rid of nitrogen so I don't have to change water.
needs refuting. There are reasons well beyond test results for ammonia/nitrite/nitrate that we do substantial weekly water changes. Pathogens, pheromones, allomones--there are no tests for any of these, but they do affect fish and weaken them which leads to further problems. With regular water changes, the biological system is more stable, and these substances are reduced or sometimes removed, which benefits the fish always. Read more in my article here:

 
I agree, the new neons carried something. This could have been an internal protozoan. Back some 10 years ago I had the same thing happen, except in my case whatever was introduced was killing all fish in the tank. It was an internal protozoan. There are no outward signs until the fish dies, behaving normal until that point. A necropsy by a biologist might determine the protozoan, but it really makes no difference because there are several (according to the biologist I consulted at the time) and by the time you isolate the species the fish will all be dead. Quarantining for several weeks is the only action to avoid this, I learned the hard way.

This comment...

needs refuting. There are reasons well beyond test results for ammonia/nitrite/nitrate that we do substantial weekly water changes. Pathogens, pheromones, allomones--there are no tests for any of these, but they do affect fish and weaken them which leads to further problems. With regular water changes, the biological system is more stable, and these substances are reduced or sometimes removed, which benefits the fish always. Read more in my article here:

Thank yoy Byron. Your article will change my behavior. I will start slowly to do water changes.
 
I agree, the new neons carried something. This could have been an internal protozoan. Back some 10 years ago I had the same thing happen, except in my case whatever was introduced was killing all fish in the tank. It was an internal protozoan. There are no outward signs until the fish dies, behaving normal until that point. A necropsy by a biologist might determine the protozoan, but it really makes no difference because there are several (according to the biologist I consulted at the time) and by the time you isolate the species the fish will all be dead. Quarantining for several weeks is the only action to avoid this, I learned the hard way.

This comment...

needs refuting. There are reasons well beyond test results for ammonia/nitrite/nitrate that we do substantial weekly water changes. Pathogens, pheromones, allomones--there are no tests for any of these, but they do affect fish and weaken them which leads to further problems. With regular water changes, the biological system is more stable, and these substances are reduced or sometimes removed, which benefits the fish always. Read more in my article here:

I concur.
 
Coming from Petco I think your tank , as nice as it is , was a shock to the new arrivals. Quarantining ? Yes ! I also think that Neons are a little touchy. If you want 12 buy 24.
Ain't that the truth.

Although I have to admit, on my last purchase (from petco) I finally got all 6 to survive, and finally have a little school of lucky 13.

It took me weeks of constantly going to the store, learning their stock arrival and transfer patterns, and plain observation of the fish at their tank. The one time I went and saw no dead ones, no strange-acting, no drain-circling swimming... I pulled the trigger.
Prior to that, only the new arrivals had died, so it seemed it was not a contagious disease, OR my established fish were strong enough to withstand it.
 
Ain't that the truth.

Although I have to admit, on my last purchase (from petco) I finally got all 6 to survive, and finally have a little school of lucky 13.

It took me weeks of constantly going to the store, learning their stock arrival and transfer patterns, and plain observation of the fish at their tank. The one time I went and saw no dead ones, no strange-acting, no drain-circling swimming... I pulled the trigger.
Prior to that, only the new arrivals had died, so it seemed it was not a contagious disease, OR my established fish were strong enough to withstand it.
That is something I never thought of. Case the joint and see what's what and how things happen at a store. I always impulse buy but I am definitely going to remember this.
 
I'm lucky to have a mom & pop nearby, I cringe to think of buying fish from Petco, or Pet"Smart"......but, they're all some people have in the US, and don't/won't buy online & have shipped

Just think....some Walmarts sell aquarium fish....*shudders*
 

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