My latest mystery (Cardinal Tetra)

[Sedridor]

Hey folks - I got in to the hobby about a month and a half ago, and have been cutting my teeth on a 10g tank which will soon become my quarantine tank. I had a problem with what I thought were probably gut parasites in my initial school of neon tetras, so I treated them with erithromycin and API's general cure to try and nail down most of the standard culprits. Symptoms were emaciation, lack of interest in food, and ultimately death for one of them. This appeared to work - I doubled the recommended duration of treatment and performed regular water changes, and the tetras regained their color and some appetite. However, they remained emaciated and have not recovered their typical shape. They remain somewhat angular and faded, and in the last two weeks I have lost one and appear to be losing another. I suspected that these two were simply too ravaged by the parasites to survive (admittedly I caught this infection too late - I wasted a lot of time thinking it was down to water quality or food type.), so I have not made additional efforts to medicate, etc since then. However, after the recommended duration of treatment had elapsed, I introduced three cardinal tetras to the tank to bolster their numbers. These have largely remained healthy since then, but yesterday I noticed some odd coloration on one of them, visible in the picture here:

I'm having some trouble diagnosing this one, but what I now suspect is that the original neons were suffering from both gut parasites leading to malnourishment, and NTD or some other wasting disease which may have been communicated to this cardinal. The most bizarre part of this is that my other fish - fancy guppies, panda corydoras, and a couple of amano shrimp, appear to be completely unaffected.

If you have any thoughts or perspective on this, I'd love to hear them, and I'm not afraid to do followup research to learn more about this stuff. I'm very new to this hobby and have a lot to learn, so even breadcrumbs are appreciated. Thanks in advance!

P.S. I forgot the most important stuff! My tank params are stable as follow:

Temp: 79F
PH: 7.5 (crushed coral in filter to regulate, varies a bit with water changes)
Ammonia: 0
Nitrite: 0
Nitrate: 0
GH: 80ppm
KH: 30ppm

 

[Delapool]

How are your fish doing?

 

[Sedridor]

Thanks for asking! I've been so caught up dealing with work and aquarium things the last couple of days that I had nearly forgotten about this thread. They're doing better! These tetras were co-located in the same tank as the Panda Cories I mentioned in my other thread, meaning the 7.5 pH I listed here was completely out to lunch. The pH was probably around 8.4 at the time this photo was taken, but I didn't realize it because both my test strips and sensor were reporting incorrectly. I was basically bleaching my fish.

This also explains why water changes seemed to be the only thing which had any immediate effect. Since time of posting, I quarantined everything except the Panda Cories and have been treating both tanks with API Gen Cure to deal with a parasite infestation. The cardinals in the above photo did not appear to have these parasites and have not exhibited any symptoms of them, but I did notice that when they were transferred to the quarantine tank (which has a lower pH because the coral is not in the filter) their coloration improved within 24 hours and their appetite gradually returned. They (and the surviving neons and guppy currently sharing the quarantine tank with them) are eating again, and are regaining their color and vigor.

I'm not completely out of the woods yet, of course - but given that this tank crash seems to have been a combination of intestinal parasites and caustic water, I feel like I got off easy if all I lost was three neons and two guppies.

 

[Delapool]

That does sound good news. I've given up on neons - all three schools I had caught a bacterial infection but in my case the colour mainly faded from the head towards the tail. As this was with cotton mouth and lesions on the tail they pretty much had no hope.


I did copy in this link in case of interest.


Neon Tetra & FNT Disease; Sporozoan Fish Infection

 

[Sedridor]

Hi Delapool,

Sorry about the delayed reply - things have been pretty hectic for me lately. I looked over the link you posted, and that looks exactly like the affliction my neons suffered from. It did ultimately kill most of them, but two remain and still appear to be making a recovery. They seem to bloat a bit more than they should when eating, though, so it's possible that the ulceration may be too severe after all. The API General Cure mix appears to have been at least somewhat effective as a treatment - I suspect this was due to its containing Metronidazole, which is one component of the bath that site recommends. I'm not sure how I feel about Methylene Blue based on what I've read, but it's good to know that it could be effective for cases like this.

Oddly, the Cardinals seem unaffected by the parasites. I'm not sure if this is because the Cardinals were not exposed as early or are more resistant to this particular strain, but they have been quarantined with the neons for weeks now and still exhibit no symptoms of infection. I will continue to monitor them over the next few weeks to ensure that the parasites have been eliminated, and will be installing a UV sterilizer on the filter return line of my primary tank to mitigate any future outbreaks.

As for neons in general . . . this will definitely be my last time buying them. They seem to shoal well with the Cardinals, so if I decide to replenish / increase my tetra population going forward, I will be switching to those. The neons were great as trainer fish, and definitely exposed me to a lot of fish ownership challenges that more robust fish might not have, so at least for that I am glad I tried them once.

Thank you for your help with this - I had given up on getting a solid diagnosis for the tetras beyond my speculation and googling, and even though it comes too late to help them much I will be better prepared if this happens in the future. I really appreciate it.

 

[Delapool]

I did find the cardinals survived better than the neons (even in the same infected school). If I did a different tank I might try them again but have gone to larger tetras. Shame as a really lovely fish. A huge school of 40 or something would be amazing.