# Neon Tetras Kept Dying in Planted Tank! Why?



## WaveSurfer (Oct 3, 2007)

Hi all,

My tank was revamped 2 weeks ago (tank and filter have been running for nearly 4 years though), with some plants added as recently as a few days ago.

I have added schools of Neon Tetras in two batches 2 weeks ago, first batch of 20 followed by another batch of 50 (from another LFS) on the following day.

They have been fine initially but about a week later, I started realising the number of Neon Tetras missing from the tank (from originally 68 till now around 50 remaining). On several mornings, I noticed a few of them behaving weirdly, like hiding in a corner or between the plants, away from the school.

This morning, I saw a few of them floating on the surface of the water, with no visible injuries but breathing their last breaths. I guess after they die, the fishes in the tank will eat up their remains, thus I don't see any dead bodies when I return from work in the evening.

So may I know what would be the likely cause for their deaths? I can think of a way off-hand but not sure if any of them are the real likely cause...

- Tetras from the first batch of 20 were already week in health so they are dying one by one, leaving the 2nd batch of 50 still healthy.
- Over-concentration of CO2? But I'm only running 1bps with adequate aeration (I believe) with the EHEIM ECCO 2233 filter working fine.
- Some disease passing among the tetras? My other fishes are so far still okay though.

Need your help for your thoughts and advices. Below are the details of the tank:

*Tank Dimensions*
3 x 1.5 x 1.5 Feet planted tank (46 Gallon)

*Lighting*
1 x T5 39W 10000K, 1 x T5 21W 6500K and 1 x T5 39W 14000K tube at about 5.5 inches from the water surface. Photo-period is 8 hours (6.30am to 9am and 6.30pm to 12 midnight).

*CO2*
1 bps. kH = 5, pH = 7. Should be around 15ppm according to the CO2 chart?

*Fert*
Dosing liquid ferts using the EI method at half the recommended amount.

* Flora*
Foreground:
Echinodorus Tenellus
(Unknown species between driftwoods)

Mid-Ground (from left to right):
Mondo Grass (non-aquatic plant but keeping them there for the moment)
Petite Nana (Anubias barteri 'Petite')
Whorled Pennywort (Hydrocotyle verticillata)
Red Ludwigia (Ludwigia repens)

Background (from left to right):
Vallisneria Americana (Gigantea)
Water Hyssop (Bacopa monnieri)
Nana (Anubias barteri 'Nana')

*Fauna*
Neon Tetra (originally 68 but now around 50 left)
Golden Cichlid (Melanochromis auratus) x 2
SAE (Siamese Algae Eater) x 3
Dwarf Loach (Yasuhikotakia sidthimunki) x 2
Panda Garra (Garra Flavatra) x 2
Albino Corydora (Corydora aeneus) x 2
Otto (Otocinclus affinis) x 3

Thank you!


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## jmowbray (Dec 20, 2009)

Sorry I can't help. However, I have a question regarding your fish. Is that a current pic with all 50? If so I guess I will have to get more. I have a 72 bowfront and was going this week to get 25....


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## WaveSurfer (Oct 3, 2007)

jmowbray said:


> Sorry I can't help. However, I have a question regarding your fish. Is that a current pic with all 50? If so I guess I will have to get more. I have a 72 bowfront and was going this week to get 25....


No problem. 

Yes, I was counting from the photo and it was around 50 of them in the tank.


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## JSA (Jun 3, 2011)

It may be that your biofilter wasn't up to the added bioload represented by such a large number of new fish all at once. And once they started dying, any missed decaying bodies would further up the ammonia.

Have you tested your water?


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## WaveSurfer (Oct 3, 2007)

JSA said:


> It may be that your biofilter wasn't up to the added bioload represented by such a large number of new fish all at once. And once they started dying, any missed decaying bodies would further up the ammonia.
> 
> Have you tested your water?


Hmm that could be a possibility indeed! Slipped my mind... Will go test the Ammonia level this evening.

May I know if there is indeed an Ammonia spike, what's the best method(s) to reduce it within a short time?


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## Geniusdudekiran (Dec 6, 2010)

Big water change. And adding 50 fish at once to a 46 gallon is usually recipe for disaster. Just keep up with testing and appropriate water changes.


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## HolyAngel (Oct 18, 2010)

Could just be bad stock/disease/infection as well, do you know how long/did you quarantine them?


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## WaveSurfer (Oct 3, 2007)

Geniusdudekiran said:


> Big water change. And adding 50 fish at once to a 46 gallon is usually recipe for disaster. Just keep up with testing and appropriate water changes.


Thanks for the advice.

Indeed, after reading some articles on the web, realised that adding such a big number of fishes within a short period may cause Ammonia and Nitrate spikes. Didn't realise this would impact the cycle of the tank, since it has been cycled for so many years already. Also read that Neon Tetras are more susceptible to spikes than other fishes.


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## WaveSurfer (Oct 3, 2007)

HolyAngel said:


> Could just be bad stock/disease/infection as well, do you know how long/did you quarantine them?


Didn't quarantine them (lazy ), just acclimate them by floating their bags in the tank before introducing them in.

Bad stock could be possible (the 1st batch of 20 more likely since that LFS didn't look too well-managed), but will probably know if it's true when the dying stops at around the 20th-mark (which is around now).

Read about the disease for Neon Tetra but the descriptions on the symptoms don't suit the cases I've observed.


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## WaveSurfer (Oct 3, 2007)

I also realise that the tetras usually appear alright when I am observing them in the evenings and nights, with the weird behaviours appearing only early in the morning so far, during the first photo-period.

Not sure if this observation is of any importance...


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## roadmaster (Nov 5, 2009)

I might consider acclimating the fish a little differently.
Pour the fish gently from the bag into a small bucket, and then add one cup of your aquarium water to the bucket every five minutes until the bucket is near full,or twice the amount of water that was in the bag. Then net the fish from the bag and release them into your aquarium or quarantine tank or tub.
Throw away the bucket of water after releasing the fish.


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## rocketdude1234 (Apr 8, 2010)

Acclimating can definitely be an issue, but it sounds like it was too much at once for the system.


I don't if anyone else does it this way, but I use what I call the 25, 50, 75 method.

Basically, I take a 5 gallon bucket and pour the fish from the bag into the bucket (so long as there is enough room for them to swim). I will add 25% of the amount of water that was in the bag from the tank. (ie, if the bag is full of 1 gallon of water, I will add 1/4 gallon from the tank into the bucket. I usually wait about fiften minutes at which point I add another 25%. 

I call it the 25, 50, 75 because I'm slowing making the water about 75% tank water. The final step is placing the fish into their new home.


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## Ben. (Mar 29, 2011)

I had a bad batch just recently, bought 5, 3 died within 24 hours.


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## WaveSurfer (Oct 3, 2007)

Thanks for the tips and sharing!


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## WaveSurfer (Oct 3, 2007)

Checked the tank's Ammonia level and it is 0... So it looks like a bad batch of Neon Tetra or some of them unable to get used to the new tank?


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## Deahttub (Apr 17, 2011)

WaveSurfer said:


> Checked the tank's Ammonia level and it is 0... So it looks like a bad batch of Neon Tetra or some of them unable to get used to the new tank?


 
I got a bad batch of Neons myself.....from what I haved heard lately is that the neons have been over bred making them a bit weak....i think im going with cardinals next as they are wild....


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## nalu86 (Oct 19, 2010)

Melanochromis auratus THIS IS YOUR PROBLEM!!!!!!

THIS IS A VERRY AGRESSIF CYCHLID THAT DOES NOT BELONG IN THERE!!


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## nalu86 (Oct 19, 2010)

M. auratus is definitely not for beginners, even though it is often purchased by unsuspecting and na�ve admirers. The reason for being a difficult or problematic fish is due to the fact that it is _]far more aggressive than_[/B] the majority of Mbuna. Adult males are perhaps the most aggressive of any Mbuna available, period. They are violently intolerant of male conspecifics (i.e., fish of similar appearance). Simply do not try and keep more than one of these males in anything less than 125 gallons. Males can be quite effective at laying claim to almost half of a 50-gallon aquarium, fighting anyone who trespasses, unless to spawn.


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## 150EH (Dec 6, 2004)

How long were they in the bag on the ride home??? I really don't see anything wrong except the amount added to a tank that was recently redone and that could be it if too much benificial bacteria was removed. Do you try to keep you water temp the same during water changes, a quick rise or fall in water temp will cause fish to get sick from underlying illnesses.


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## nalu86 (Oct 19, 2010)

150EH said:


> How long were they in the bag on the ride home??? I really don't see anything wrong except the amount added to a tank that was recently redone and that could be it if too much benificial bacteria was removed. Do you try to keep you water temp the same during water changes, a quick rise or fall in water temp will cause fish to get sick from underlying illnesses.


Come on, this has nothing to do with this right now!
He has a very aggressive cychlid in there that should be removed right away.

The fish is stressed out and tired from chasing, thats why they gasp for air and heavy breathing.

People have to learn to read the whole post and then start posting about what the problem could be.


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## flip9 (Jun 16, 2011)

If you find they a lot of them are starting to losing color it might be neon tetra disease.

The agressive cichlid would be my first bet though


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## BradH (May 15, 2008)

Deahttub said:


> I got a bad batch of Neons myself.....from what I haved heard lately is that the neons have been over bred making them a bit weak....i think im going with cardinals next as they are wild....


There is a fish farm in florida that alot of store get their cardinals from and they breed them there in Florida.


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## WaveSurfer (Oct 3, 2007)

nalu86 said:


> Melanochromis auratus THIS IS YOUR PROBLEM!!!!!!
> 
> THIS IS A VERRY AGRESSIF CYCHLID THAT DOES NOT BELONG IN THERE!!





nalu86 said:


> M. auratus is definitely not for beginners, even though it is often purchased by unsuspecting and na�ve admirers. The reason for being a difficult or problematic fish is due to the fact that it is *far more aggressive than* the majority of Mbuna. Adult males are perhaps the most aggressive of any Mbuna available, period. They are violently intolerant of male conspecifics (i.e., fish of similar appearance). Simply do not try and keep more than one of these males in anything less than 125 gallons. Males can be quite effective at laying claim to almost half of a 50-gallon aquarium, fighting anyone who trespasses, unless to spawn.





nalu86 said:


> He has a very aggressive cychlid in there that should be removed right away.
> 
> The fish is stressed out and tired from chasing, thats why they gasp for air and heavy breathing.
> 
> People have to learn to read the whole post and then start posting about what the problem could be.


Thanks for the reminders.

Indeed, the two cichlids in the tank can be quite aggressive at times (they are a pair of father and son) but during the times when I'm observing them, they usually keep to themselves and do not bother the other fishes. That's why I thought these fishes can still live quite well together.

However, being reminded of how aggressive they potentially can be, it makes me wonder if they have a different behaviour altogether after the lights are turned off every night. Could they actually be displaying their true aggressiveness against the tetras during these lights-off periods, thus the reason why I always find dying tetras only in the early mornings?

Although I love watching them (as they are usually quite peaceful), I do admit that they may be posing problems for the other fishes, and also causing some scaping issues in the planted tank due to their characteristics for moving the gravel.

The problem is on what to do next; there's no other tank available to house them so the alternative will be to give them away?


flip9 said:


> If you find they a lot of them are starting to losing color it might be neon tetra disease.
> 
> The agressive cichlid would be my first bet though


When they are dying/dead, their colours still remain, so I don't think it's a disease.


150EH said:


> How long were they in the bag on the ride home??? I really don't see anything wrong except the amount added to a tank that was recently redone and that could be it if too much benificial bacteria was removed. Do you try to keep you water temp the same during water changes, a quick rise or fall in water temp will cause fish to get sick from underlying illnesses.


The journey was around 30 minutes. As for water change, usually I don't do a big change (around 5% plus top-ups due to evaporation) so I think temperatures shouldn't change too much.


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## nalu86 (Oct 19, 2010)

WaveSurfer said:


> Thanks for the reminders.
> 
> Indeed, the two cichlids in the tank can be quite aggressive at times (they are a pair of father and son) but during the times when I'm observing them, they usually keep to themselves and do not bother the other fishes. That's why I thought these fishes can still live quite well together.
> 
> ...


They probably start hunting like crazy at night.
You never had any prob with your fish before just because they are all quick fish, and probably can hide in the plants or decor.

Neon Tetras are slow and a great prey for hunting fish. Surtainly at night when they just hang in the water.

You should turn off your light in the evening and just leave a moon light on and see what happens. Also turn the light off in the room, its quit fun watching how they hunt but your other comunity fish won't love it 

Just take them out, sell them to your LFS or buy a big tank and start an Mbuna Cichlid Tank. Don't let your other fish suffer, because you like them in there.


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## WaveSurfer (Oct 3, 2007)

nalu86 said:


> They probably start hunting like crazy at night.
> You never had any prob with your fish before just because they are all quick fish, and probably can hide in the plants or decor.
> 
> Neon Tetras are slow and a great prey for hunting fish. Surtainly at night when they just hang in the water.
> ...


Okay thanks for the suggestions.

I will probably put them up for adoption on the forum since the first two options might not be viable for my case.


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## WaveSurfer (Oct 3, 2007)

Another question: How do I fish up the two cichlids with minimal disturbances to the plants etc? The last time I tried to catch them, I had to basically empty the tank to net them as they are very quick and smart.


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## nalu86 (Oct 19, 2010)

I had to do the same, empty the tank and take all of the rocks out. 
If you do it when the lights are out it should go faster.

good luck!!


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## flip9 (Jun 16, 2011)

Use 2 fish nets and corner them.


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## WaveSurfer (Oct 3, 2007)

nalu86 said:


> I had to do the same, empty the tank and take all of the rocks out.
> If you do it when the lights are out it should go faster.
> 
> good luck!!


I'm not going to empty the tank again this time, after spending so much effort to set it up... 


flip9 said:


> Use 2 fish nets and corner them.


Okay thanks, will try that!


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## dysorder (Oct 9, 2008)

I had the same exact issues yesterday with a batch of Neon's. As soon as I added them to my main tank after QT, they were immediately gasping at the surface. I netted them put them back into the QT bucket I used to transfer and they all appeared fine. I turned off my CO2 completely, added the neons back to the main tank and they all appear fine. I plan on turning the CO2 back on when I get home from work in about 3 hours. I've never had issues in the past with CO2 gassing newer fish to my tank.


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## WaveSurfer (Oct 3, 2007)

dysorder said:


> I had the same exact issues yesterday with a batch of Neon's. As soon as I added them to my main tank after QT, they were immediately gasping at the surface. I netted them put them back into the QT bucket I used to transfer and they all appeared fine. I turned off my CO2 completely, added the neons back to the main tank and they all appear fine. I plan on turning the CO2 back on when I get home from work in about 3 hours. I've never had issues in the past with CO2 gassing newer fish to my tank.


May I know what is your CO2 dosage rate and how big is your tank?


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## dysorder (Oct 9, 2008)

55G tank around 3 bps with pressurized CO2.


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## WaveSurfer (Oct 3, 2007)

dysorder said:


> 55G tank around 3 bps with pressurized CO2.


I see.

Mine's already set at a very low rate of 1bps, so wasn't expecting the fishes to behave so badly. Prevents me from setting the CO2 any higher...


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## WaveSurfer (Oct 3, 2007)

Okay, I believe I have concrete evidences that the two cichlids (or one of them) could likely be the culprits behind the tetras' deaths.

A few more died/disappeared when I returned back from work, and I spotted a few in the school that were swimming weirdly. Upon closer observation, I saw two to three of them had their tails cut off, and one to two their fins broken.

One of the injured tetras with its bottom fin missing:










I then set up a trap using a plastic bottle that had been cut into half, with the top inverted and slotted into the lower half. I had read about this trap idea from a website.










After putting two pieces of wafers into the trap, I placed it on the gravel and within minutes, the bigger cichlids went in and I immediately lifted up the trap and put him into an isolated tank. The trap is very effective indeed!

Following that, I placed the trap back again, hoping to catch the smaller cichlid. Unfortunately, the greedy eldest SAE went in instead and got itself trapped!

I tried to release him asap but by then, he was already in shock and had one of its scales chipped off while it was struggling in the trap. 










Putting the trap back again, it was in another few minutes' time that I caught the smaller cichlid, together with a garra and chain loach.

With that, both the cichlids were now safely isolated from the other fishes, and I'm trying to contact the interested adopter to pick them up.










Hopefully this will be an end of the vanishing tetras...

I am worried about the injured SAE though. With one scale missing, will he be prone to fungus infection and if so, what can I do to help?


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## doncityz (May 17, 2011)

OMG! I know this guy. Melanochromis Auratus. One of the badasses of the cichlids. 

Cichlids should never be mixed with other fish. Even when grouped with their own kind, they kill each other if there is not enough space. 10gall is fit only for 2 cichlids.


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## WaveSurfer (Oct 3, 2007)

doncityz said:


> OMG! I know this guy. Melanochromis Auratus. One of the badasses of the cichlids.
> 
> Cichlids should never be mixed with other fish. Even when grouped with their own kind, they kill each other if there is not enough space. 10gall is fit only for 2 cichlids.


Sigh... They didn't look so dangerous to me whenever I'm watching the tank. 

Don't really bear to give them away but guess I don't have a choice.


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## nalu86 (Oct 19, 2010)

doncityz said:


> OMG! I know this guy. Melanochromis Auratus. One of the badasses of the cichlids.
> 
> Cichlids should never be mixed with other fish. Even when grouped with their own kind, they kill each other if there is not enough space. 10gall is fit only for 2 cichlids.


Like I said.

I don't understand that people started asking about the acclimation of the neon tetra and the co2 in the tank (1 bubble in a 55 almost doesn't make a differences btw)... If you read the discription, you can read that he has those 2 cichlids in his community tank.... how can you read over that.

I can only say on this one, if you don't read posts, don't answer them :icon_neut!!

And for wavesurfer, hope you learned your lesson


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## Coursair (Apr 16, 2011)

I'm surprised someone sold you that mix of fish. I always ask what is in the tank. Or if you bought African Cichlids as the same time as Neons I would have asked if you had separate tanks. 

Petsmart may be many things but at least we label Africans with a red tag and Neons with a Community tag. 

Glad you got your Cichlids out of the tank.


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## WaveSurfer (Oct 3, 2007)

Thanks folks. 

Still waiting for the adopter to contact me to pick up the cichlids. I hope they will find a good home ahead.


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## WaveSurfer (Oct 3, 2007)

UPDATE: Meeting up with an adopter for the two cichlids either tomorrow or Saturday morning. Hope they will live well in their new homes. I'll probably miss them for a while...


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## WaveSurfer (Oct 3, 2007)

UPDATE: Sent the 2 cichlids to their new owner just moments ago... More details here.


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## flip9 (Jun 16, 2011)

Good to hear. 

If you want to cichlids in the future, Get dwarf cichlids like Blue/German Rams or apistogramas as they get a long with neons just fine


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## CRShark (May 7, 2015)

*tetras and CO2*

No, I think you are on to something. I have a fairly heavily planted tank (Swords, some sprite) have a 130 with about 150 cardinals. While I find that they slowly disappear ( 1 -3 /month) I recently added a CO2 tank w/ regulator. I haven't measured my bsp (what are you using in the cyclinder, water or oil?) but I have a CO2 detector right above the riser, so I can monitor it closely. However, I have been noticing that within an hour or so of turning on the CO2, I see 2 or 3 tetras whirling around, like whirling disease. Haven't actually seen them die, but like you, they could be eaten by the snails and other fish within hours. Seems odd, since my CO2 levels seem to be low and I have lots of plants, but certainly is a coincidence.

Craig

[email protected]


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