Reptile & Amphibian Forums

Hey everyone... So I am having an issue with my 29 gallon tank. It has been set up for over 8 months now, and has quiet a few live plants in it: 3 Anubis, 6 Java Fern, 2 Amazon Sword, 1 Pennywort, 1 Moss Ball, and 1 Crypt. The tank is equipped with an AquaClear 50, temps on two thermometers read 77.7 and 78.7. Ammonia-0, Nitrate-5, Nitrite-0, Alkalinity-40-60, and pH-7.0-7.2. Maintenance is easy on this due to the all the plants, the size of the water changes is based on Nitrate levels, the level has never been above 10 in this tank. The changes are usually minimal, 25-35%. Beneficial bacteria is added after any fish are added, after water changes and bi-weekly to main the biofilter. I am having a problem with my Dwarf Neon Rainbows. I had a school of 5 and they were dying one by one over the last week. The last two I found this morning. I also lost a small angelfish previously to them dying. I am not sure what the cause is... I have two other angels doing beautifully, growing and eating like champs, 8 neon tetras also doing very splendidly. In addition to them, I have one Rosaline shark (I know he should have a school, but he was the only healthy one they had at the time, and he has a friend waiting on him to get get bigger to move to the 100gal.) 3 L/F Red Minor Tetra and two Redhead Eartheaters. The Eartheaters will also be moving to the 55 when they out grow the 29 and then to the 100 gal when they out grow the 55. there are 3 cory cats and about 8-10 ghost shrimp. I am not a novice at the hobby... still have some stuff to learn, but have had tanks for a few years now, and all of them doing well. Please help if anyone has any ideas... Also the Rainbows were the first to go into the tank.

We ALL have things to learn still, that's the beauty of life.

There are a couple things I can think of that could be the problem: 1) Your water changes should be 20% biweekly, however since your tank is still going strong until now I would say that's not the likely answer. However, if you haven't been doing the gravel maintenance there could be dead zones under your gravel, and if anything stirs them up all the toxic ammonia moves into the tank and kills the fish. But if that is a recent water reading, that is unlikely too.

2) The dying fish are old. This is possible unless you got your fish from a breeder, which I don't think you did. If you got the fish from a pet store, you never know how old they are.

All your other fish are still doing well? Was there anything out of the ordinary that you saw in the fish that have died?
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Phishie
Site Coordinator

"An ounce of prevention is worth a pound of cure."

They Rainbows didn't have any visible marks, lesions, lumps, bumps, or anything. I did notice on the last two that died, they did have labored breathing 24 hours before they died... I assumed with the death of the first one that it was age... but then I lost a second, and by the third I ruled out age, that seems way too coincidental that all my Rainbows reached the age of passing at the same time, all within one week... Also, none of the other fish have showed any signs of stress, labored breathing, nothing. All are well, eating regularly, and acting normal. The first two Rainbows that died did not show any signs of illness or stress, they were just dead when I found them. The third one to pass did have some labored breathing, but still ate 24 hours before passing. The last two had labored breathing, and did not eat before passing. I am just so stunned by this loss... I hate when fish die, but it seems worse when there are no warning signs... I have lost fish in the past, but usually you can find an underlying cause... This one I can't.

Thank you for all your input, I really appreciate the help.

It is still possible that one of the deaths could have been old age, but I do agree that that many... there has to be another reason. It is possible, since you did see some with labored breathing, they may have had gill disease, although towards the end the gills become inflamed. It was a tough one for me to diagnose when my betta had it. You could add some melafix/pimafix (even use them both at the same time) as a preventative for now... just one time to prevent any other deaths (hopefully).

Given your descriptions and water parameters, there's nothing else I can think of that would cause as many deaths as you've had recently. It almost seems like ammonia poisoning, but your ammonia level is fine. Seems like you give them a good, clean home and I really hope the deaths stop for you. If you do the melafix/pimafix combo, and your other fish are not in fact ill, it will not harm them in any way. They're pretty natural treatments.

I'm sorry I cannot pinpoint exactly what's going on; it's very strange to me.
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Phishie
Site Coordinator

"An ounce of prevention is worth a pound of cure."

Well, thank you for the input. I found it very strange myself. A friend said that could have been something that just affected the Rainbows, almost like a disease that only affects them. That is about the best thing I can believe in at this point. Everyone is still doing so well, and not showing any signs of stress or sickness. Thanks again!!!