Cardinal Tetra Mortality

[dasaltemelosguy]

Hello, I'm not sure this is the correct category to post this but perhaps someone with experience with Cardinal Tetras may know what might be going on here. It has a SunSun704b canister and the output was modified to distribute the spray across the entire length to reduce the current so they could eat on top or in the column. I try to over filter my tanks and accommodate these tiny fishes. 

I have a 75G planted tank that has been cycled for months as I've used it for grow out of juvenile cichlids until they're large enough to join a larger tank. The parameters below have been extremely consistent for many months:

• pH = 7.8
• Nitrates = 5ppm
• Hardness = 140
• Nitrite = 0
• Ammonia = 0
• KH/Buffer = 70
• Water Temperature = 80*

One day prior to this population below, it housed 12 adult Blue Acaras, two juvenile plecos and a juvenile algae eater. The Acaras were moved to a 120 and the following day, the juveniles below arrived. 

In this tank now (for about 2 weeks so far), I have 12 juvenile Silver Dollars (about 3/4" in size) and 50 circa 3/4" Cardinal Tetras. The Dollars love it. Actively swimming end to end in schools and no visible shyness. The Cardinals look robust and school as well as explore the tank and as far as I can tell, all of them eat well. The little algae eater and small plecos are active and eat well too (obviously they're in here for grow-out) . 

Every day since getting the Cardinals, I lose about 2-3 of them/day. I don't sense any stress or obvious illness and I see nothing extremely on them. I find a dead ones in seemingly perfect condition lying on the gravel throughout the day which naturally I remove. Each day I find more bodies. No evidence of trauma, I'd have to pick them up and verify they're dead.

After two weeks, there's perhaps 1/2 of them left.  

I have never kept Cardinals before. They currently share this 75G with two juvenile plecos and a small algae eater (also in grow-out) and the aforementioned 12 Silver Dollars. NONE of the others exhibit any sign of distress nor illness. Very active, eating and already visible growth. And the surviving Cardinals eat voraciously yet ONLY the Cardinals seem to be slowly dying. 

When I bought the school of 60, I assumed there would be some mortality with that many but there's now less than half of them left after only 2 weeks. 

I did ask the shop where I got them and they said "they were acclimated to a 7.4PH environment". When they arrived, the PH in the bag was 6 so I set up a drip overnight and introduced them into my tank at 7.8PH at which point, they matched. 

At that point, I had only 9 die and the other 50 were looking excellent. 

I have no experience with these fishes. I've only kept large cichlids and this is my first foray into schooling fishes. And I should note it is planted but not heavily. I'm not confident there are enough hiding places for the Cardinals. 

I see a great deal of discussion about PH for Cardinals but I was wondering if others had ideas on how truly significant that is. With most fishes, if properly acclimated, they'll adapt to most any PH. 

But again, I've never had Cardinals. My other tanks have Severums, Acaras, Oscars, Pacu's, Plecos, all grown from <=1" to +14" in some cases over 2+ years with very few incidents. I've never had an entire species just start dying with no apparent (to me) cause. 

Does anyone out there have any thoughts on what I might be doing/have done wrongly that is killing off the Cardinals and if it's possible to save the rest? Thanks so much everyone. 

[Colu]

It's possible when you drip acclamated them over night you got an ammonia spike in the bag ammonia can kill fish days and weeks after being exposed to high levels

[dasaltemelosguy]

Thanks. That's certainly a possibility. I did try to detoxify their water in their bucket with Prime, knowing there would be a build-up (although it's hard to know how much protection it offers, especially for small, highly stressed fishes) and of course, the drip water was ammonia-free. But it still certainly could be a possibility. To be honest, when I saw the PH disparity, I didn't know which would be worse, an overnight drip or a PH shock as their PH in the bag was only 6 and their destination tank was 7.8!

Edited August 27, 2021 by dasaltemelosguy

[Colu]

It could be but some cardinals can be delicate at frist and no unusual for you to some fish if you not seeing any symptoms it possible it could be an internal bacterial or stress that pushing them over the edge 

[dasaltemelosguy]

Thanks again. I hesitate to replace them yet as I don't know why they're perishing but you're probably right, this batch was injured by shipping or by my actions. 

I was concerned about the PH as you read so much about their preferring a lower PH but most fish will adapt to a given PH if given enough time.

I could be wrong but would doubt the absolute value of the PH would outright kill them so long as they had proper acclimation time but I have 0 experience with these fishes. 

So I'm unsure if I gave them enough PH acclimation time (overnight) or if they simply will never tolerate a PH of 7.8? The latter seems doubtful but I'm open to suggestions!

[Colu]

Lots of people keep cardinals at a higher pH I don't think that the problem when I drip acclamate fish I only do it for a couple of hours depending what type of fish it is and add a drop or two of prime  as it sopose to detoxify ammonia and nitirte to say wether it actually works I haven't read anything disproving the efficacy of prime in detoxifying ammonia or nitrites I would consider doing a course of maracyn or kanaplex just in case its an internal bacterial as you still losing fish 

Edited August 27, 2021 by Colu

[Intuos]

Do you know if they were wild caught or captive bred? In my experience wild caught can be fragile and always seem to do better when there is a good level of tannins in the water. 

[dasaltemelosguy]

That's a very good question. I don't know. I bought them at Jack Wattley Discus who were very helpful and included 20 additional fish which I assume is to cover an expected mortality in shipment. But i will ask as that's a good point. Thanks. 

[Jungle Fan]

In my experience Cardinals caught in the wild like those from Project Piaba tend to in the long run be healthier than farm raised, however, that said they sometimes can have a harder time adjusting with higher pH and 7.8 is at the upper end of what they prefer  also you can have an occasional batch that might have some internal parasites, but I would likely first look at lowering pH.

[Mmiller2001]

Did you track the temperature of the water they were in over night?

[dasaltemelosguy]

Hi, yes, it was a very regulated acclimation insofar as constants within my control. The temps were constant at 80* as is the destination tank. And the water was treated with Prime and had zeolite in the bucket. I suspect Byron is right. Either the PH change was too much in too little time or the ammonia spiked in concert with the PH rising. I made a poor choice thinking I was sparing them stress.  

On a tangential note, I LOVE your tanks. I just took a quick glance for the moment but it's just stunning work. 

[Mmiller2001]

On 8/27/2021 at 9:46 PM, dasaltemelosguy said:

Hi, yes, it was a very regulated acclimation insofar as constants within my control. The temps were constant at 80* as is the destination tank. And the water was treated with Prime and had zeolite in the bucket. I suspect Byron is right. Either the PH change was too much in too little time or the ammonia spiked in concert with the PH rising. I made a poor choice thinking I was sparing them stress.  

On a tangential note, I LOVE your tanks. I just took a quick glance for the moment but it's just stunning work. 

Thank you.

My gut tells me ammonia. pH wouldn't concern me, especially with a drip acclimation. I use to drip acclimate, I'll be honest, drop and plop has been no different from drip. 

I've killed many fish in other ways though!

[dasaltemelosguy]

Thank you everyone. I must admit, I've never seen anything like this but perhaps I was just lucky before.

The cardinals were dropping dead at a rate of 2-3/day but they seem to have stopped dying. It was the oddest thing in that they looked beautiful and were active and eating with vigor. They would eat and literally drop dead minutes afterward. Not a blemish or indicator I can see so I assumed I injured them with improper acclimation. 

It's been 7 days and the cardinals have not seen a death and I was seeing 2-3/day 'drop out of the sky' if you will. They are active, nice round bellies, great color and even growing a bit. 

Then this started. I had 13 (very) juvenile Silver Dollars growing out with them in a 75G. Very small guys, no bigger than the cardinals when I got them 2 weeks ago, more Dimes than Dollars right now. They just started dropping dead like the cardinals.

However unlike the cardinals, there are visible issues at hand on the Dollars. 

Symptomatically, I see nothing. They swim around and seem relaxed as Silver Dollars go. They swim, together and in schools, they eat voluminously, and they've clearly grown since I got them only 2 weeks ago. Not shy, they excitedly come to the top when they see you. It looks like all is well.

All of a sudden, 2 days ago, they started dropping dead like the cardinals did a week ago. With the Dollars I find a dead one every day but I saw no signs of distress nor illness until 2 days ago. 

I've been keeping fishes since the 1970s and this is the first time I've encountered what appears as active, healthy fishes seemingly dropping dead without any symptoms. Like I said, perhaps I've been lucky in that ich was the worst disease I've ever encountered with fishkeeping until now! 

Would you mind taking a look and giving me your opinions on what this might be? I have started a Nitrofurazone/Kanamycin treatment 2 days ago when I saw this as it seems like columnaris but I've never seen it before so I'm very much uncertain as to what's wrong. 

On the tank, it's long been cycled, ammonia=0, nitrites=0, PH=7.4 and nitrates are 5ppm. It's a 75G planted tank with now, 20 cardinals and 10 Silver Dollars about the size of a dime at present, hence the lack of nitrates. 

It was serving as both a grow-out for the Dollars and a QT for the entire bunch. Any advice on what this might be would be most welcome! Thanks all. 

Edited September 3, 2021 by dasaltemelosguy

[Colu]

Columnaris has a white fluffy appearance which a don't see  on your pictures but can't rule it out I would Keep treating with nitrofurazone and kanamycin he's how I treat Columnaris

 

Edited September 3, 2021 by Colu

[dasaltemelosguy]

Thank you so much Colu. One quick question if you will.  I ask because despite the mortality, they all still eat well.  Is it safe to medicate the food with nitrofurazone and kanamycin?

[Colu]

On 9/3/2021 at 2:53 AM, dasaltemelosguy said:

Thank you so much Colu. One quick question if you will.  I ask because despite the mortality, they all still eat well.  Is it safe to medicate the food with nitrofurazone and kanamycin?

You can treat with Kanamycin in food  nitrofurazone is antibiotic that treats external bacterial skin infections adding it to food wouldn't improve its effectiveness he's a food recipe for kanaplex

[dasaltemelosguy]

Thanks so much.