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I have a 10 gallon tank with 3 Platies and 4 Peppered Cories.
I have never done water tests until this past next. And this tank has been heathy since the day it's been started, a little over a year ago.
My Cories' tails have been slowly eroding in the last couple months. So I just assumed it was high Nitrates, even though I've always done weekly water changes. I started changing more water each, but that had no effect.
So tonight I decided to buy a Nitrate test kit and also some Hornwort. I decided to test right away before I added the Hornwort and before I did my water change. The test showed less than 5ppm.
Question #1: With the Nitrates topping out at less 5ppm, I know it's not the Nitrates causing the fin erosion. But, what else could be causing this?



Edit: Opps, I think I should have posted this in the Water Quality section. If any mod wants to move this, go right ahead.

Edit #2: deleted question about hornwort

Last edited by T/A at 07-Feb-2005 12:54

I can't answer your question about the Hortwort but..

Are you sure that you are reading the test kit right or that the test kit is not malfunctioning? Maybe take a sample to a local fish store and have them test it and compare it with your results to make sure you are getting an accurate reading.

A tank where the tailfins of the fish are slowly eroding over a couple of month period is not a healthy tank. It basically means that the fish have adjusted to the deteriorating water conditions as best they can.

Check your pH and your ammonia and if there is ammonia present test your nitrites as well. If you don't have test kits for this have the fish store test for these as well.

Is this tank aerated?

It actually sounds like fin rot, a condition caused by bacteria.

The following is from FreshWaterAquarium.com:

Description: Fin rot is one of the most common, and most preventable, diseases in aquarium fish. It is caused by several types of bacteria, and often occurs concurrently with other diseases. It can usually be cured, but if left untreated, it can kill the diseased fish and infect all the others in the tank.

# Symptoms: Fin edges turn white
# Fins fray
# bases of fins enflamed
# Entire fin may rot away

The fins begin to fray and get ragged, becoming shorter over time. Usually the edges look white, and may even develop a fuzzy growth due to secondary Cotton Wool infection. A the disease advances the area may become red an inflamed, with bloody patches appearing as more of the fin is eaten away.

Treatment :
# Correct root cause
# Water change
# Treat with antibiotics
# Addition of aquarium salt

Fin rot is caused by one of several gram negative bacteria. Several anitiboitics are effective, however the root cause must be addressed as well.

Fin rot occurs when the fish is stressed for some reason. The most common cause is poor water quality. Overcrowding the tank, feeding outdated food or overfeeding, and moving or handling the fish can also cause stress leading to fin rot.

Treatment should include a water change, and careful examination of the aquarium conditions. If there is food debris, vaccumm the gravel and take care to avoid overfeeding. Start dating your fish food, as it loses the vitamin content fairly quickly after it is opened. Feeding fish fresh, high quality food, in smaller quantities is far better than frequent large feedings of stale foods.

Check the pH and water temperature of the water, and make sure it is appropriate for your fish. Incorrect pH is very stressful for fish, and can lead to disease. Low water temperatures, particularly in fish with long flowing fins, can trigger fin rot.

If the root cause is corrected, antibiotics will usually cure the disease itself. Use a drug that is effective against gram negative organisms. Chloramphenical, Oxytetracycline, and Tetracycline, are good choices. Treat according to manufacturers instructions.

The use of aquarium salt will benefit livebearing fish, but should be avoided in fish, such as scaleless catfish, that are sensitive to salt

Prevention:
# Maintain good water quality
# Keep proper water parameters
# Feed fresh food in small amounts

The best prevention is good aquarium maintenance. Change the water regularly, vacuum the gravel, and monitor the water chemistry. Do not overcrowd the tank, and watch for signs of fighting between fish.

When feeding, keep the volume low! Overfeeding is the most common mistake made by all fish owners, and contributes to poor water quality. Be sure to use fresh foods. If the can has been open for half a year, it has lost most of its nutritional value. Purchase food in small enough containers that it can be used in one to two months.

Last edited by Bob Wesolowski at 06-Feb-2005 19:20

__________
"To steal ideas from one person is plagiarism; to steal from many is research."
researched from Steven Wright

This tank is not aerated, it just has the Penguin filter.

I know I tested correctly the first time, but I did it again. And again it came out right about 5ppm. I also tested my tap water at 0ppm. I tested another one of my tanks at about 8ppm. Then just to be sure, I tested my brother's neglected tank at about 150ppm. And since his fish continue to die off, I have no doubt my tests are accurate.

I also tested for pH, ammonia, and nitrite last week. The tank in question had a 7.8pH and 0 reading on both the ammonia and nitite tests.

I do believe something is wrong in this tank, that's why I started this thread. But, I don't believe it's fin rot. I haven't seen any other signs that would point to fin rot.


I just re-read the lastest issue of AFM. In the one article, they stated the fin erosion can be caused by even a trace amount of chlorine. That's what I now believe it is. After thinking about it, I stopped using my water conditioner a few months ago, because I had been reading negative things about conditioners with aloe vera. All I have been doing is letting the water sit out for a few days prier to the water changes. So I'm assuming that my water does contain chloramines and I've been unknowingly adding this to my tanks. Over the weekend I also bought some Prime. I'm going to continue using this for the water changes and hopefully I'll start seeing some regrowth of their fins.

T/A,

Fin erosion can also be caused by ammonia burning fins. An indicator would also be inflamed gills and rapid respiration. Good luck, in running this down. By the way, Prime also neutralizes ammonia!

Last edited by Bob Wesolowski at 08-Feb-2005 07:20

__________
"To steal ideas from one person is plagiarism; to steal from many is research."
researched from Steven Wright

Yeah, I realize that. But, the only way my tanks could have ammonia is if my tap water contained it. All the tanks are completely cycled and have been for many months. And as you said, using the Prime would also take care of that.

Ohhhh... I'm sorry, I forgot about this thread...

T/A, I would consider adding air to this tank. It can't hurt and it might actually help.

If the tailfins are eroding, it is a form of finrot. Because you don't see any white tinge along the edges just means that it hasn't progressed to a critical point. All you need to do is make adjustments to how you do your maintenance to correct the problem.

The pH is alittle high. Adding the air to the tank should help drive that down slightly. That should help as well.

Because this is a small tank, how much water do you replace during your water changes? The next time you do your regularly scheduled water change, test your pH just prior to the change and then again 30 minutes after the change. See if there is any difference between the two.

Last edited by Tammy at 09-Feb-2005 03:28

First off, I'd like to ask how quickly do fins grow back?
I know it hasn't even been a week since I used the Prime and added the Hornwort, but all of the Cories seem to have some new growth on their tail.


I change 2 gallons every week on my 10 gallons.

When I tested my tanks pH, I also tested my tap water. Straight from the tap, it read 7.0. After letting the tap water sit for about 20 minutes the pH was 7.4. But since I leave my water sit out a few days prior to water changes, I just assummed the pH would be even closer. I'll give your suggestion a try. This weekend I'll test pH before and after the water change.

I have a 4" air stone in one of my other tanks. And I have a few more stored away if ever needed. But, I'm not so sure I want to add the air stone to this tank. I just added some floating Hornwort. With the Penguin 125 filter and an air stone in a 10 gallon tank, will the Hornwort be able to survive? I think that might be pushing it.

My concern is more about the fish surviving than the plants.

Does a slightly high pH have anything to do with fin damage?
I read as much as I can about this hobby. And I don't ever remember reading about that.
I know your only trying to help, so thanks for that.

Yeah, that is my main priority, to help the fish. Thank you for understanding. You could always pick up a small airstone.

Yes, a high pH could have an effect but more than a high pH is a continually fluctuating pH.

Alright, like I said before, I'll do same more pH tests this weekend. I'll be sure to post the outcome. Stay tuned.

Just as a side note, I now have some baby Platies in this tank. I'm not sure how many there are bacause they are mainly hiding in the Hornwort. I knew I might encounter this when I bought the male. But, now that it's beginning I'm a little concerned. The male Platy might be getting moved into another tank soon. I don't want to be overrun by this. And I'm not yet able to set up my 25 gallon.

Update:

Last weekend I was in a rush and couldn't do the pH tests. Hopefully I can get the tests done this weekend. Then I'll post the results.

I also just removed the Hornwort from the Cory/Platy tank. The survival rate would have been way too high with that plant in there. Now at least I will be able to handle the number that will survive.

As for the Cories, their fins are almost completely grown in now. All of them have a full triangle shaped tail. And the pointed tips are now starting to grow in.
From all the replires I got about this, nobody else seemed to agree with my thought. But since the only thing I have been doing differently is using Prime each week, I still assume the erosion was caused by a slight bit of chlorine in the tank. I'm just happy to see those tail fins again.

T/A...

I don't think there is any question what caused this to happen once you told us about the potential for chlorine poisoning. That was a given. What is important is that you found the cause and corrected it and the fish are recovering.