Death of the Swordtails...

[Kallen]

hey guys..i have one that I am not sure about...

I didn't post this in Disease because it doesn't seem like an illness, but then, I have no clue if it is or not...

i have a 90gal community. Quite a few swordtails (born in this very tank) some mollies, a couple cory, some danios, some small tetras, and a couple (same species) I can't at the moment recall. Today, i noticed 2 dead swordtails. A little later, another. 8 dead today.

I looked them all over. NO sign of illness whatsoever. The fins looked perfect, their eyes looked good, no discoloration or bloating. Overall, they all looked to be in perfect health.

Whatever happened, did not affect anything else in my tank. I did a 2/3 water change (yes, I know this was a but much, but out of fear of disease I wanted to remove as much water as possible). New carbon in both filters (350 Magnum and a Penguin 300).

I did get a sample of the water before I changed it:
Ammonia: 0
Chlorine: 0
Nitrite: 0
pH: 7.2 (My tap is high ph so I buffer to about 7 - 7.5)

So, what would suddenly affect JUST swordtails? It seems to me that the water tests came out good, so not issue there.....

 

[brian1973]

I have had mollies become very aggressive as they age, even to the point of killing other fish.

What have you been feeding, have you done anything different?

did you witness any strange behavior?

What is the nitrate reading?

I personally dont think 2/3 is to much I typically do anywhere from 50 to 75 percent.

I have had mysterious fish die offs before and never found a definant cause, when it happened it effected my livebearers first then moved onto the other fish, i am not sure why my live bearers where effected first or what did it, I have some ideas but no real evidence. Hopefully we can figure out a root cause before you suffer any more deaths.

EDIT can you also please include your complete stocking including numbers

 

[lauraf]

Kallen, I've also had mystery deaths when the water conditions were all in range, and nothing different had been done. When two of my fish that I had bought around the same time (a platy and a cory), and had for over a year, just keeled over, the best guess with input from the fine folks here was that it was simply old age. How long have you had the swords?
And yes, nitrate is also very important to test for - you can have high nitrates without the nitrites or ammonia spiking.
And up to 75% water change is fine. As long as you aren't changing the filter media, just cleaning it in old tank water, you won't be affecting your cycle.

 

[littletankbigworld]

Do you have copper pipes in your house or dose your water with plant food that contains chelated copper? I've had a few mystery deaths in my time and some of them have been because there are high levels of copper in my water. You could purchase a liquid copper test kit.

 

[Kallen]

I had planned on testing Nitrates, but for the life of me I can not find my nitrates test kit! It's not with my test sets. This is not something I would just have out playing with so I have no clue where it is. I didn't keep a sample of the pre-changed water....

When I do a water change, I change 50%. I thought this was more than recommended, and was certain 2/3 would be too much. As for the media, I left the 4 bio wheels alone (2 on each filter system) but did rinse the foam insert of the magnum and replaced the carbon in both filters.

3 more swordtails died today.

The current census of the 90gal is:

11 Red Swordtails (NOT the blood reds) (Down from 22)
7 Gold Barbs
6 Small Zebra Danios (both regular and longfin)
1 Large Zebra Danio
1 Pleco
2 Albino Cory Cats
2 Black Molly
5 Gold Neon Tetras (I think they're gold neon)
2 Albino Buenos Aires Tetras

Thanks for the replies!!

 

[brian1973]

do you know the sex ratio of your swordtails and your mollies?

 

[Kallen]

Both mollies are female. The swordtailes i believe there is only 3 maybe 4 males left. Of the original number over half were females.

 

[brian1973]

not a definite answer, but keep on eye on the mollies, my females got more aggressive as they aged even to the point i had to separate them into their own tanks.

 

[Kallen]

I have been watching but I have no aggressive behavior by any of the fish. Also, the 3 that dies today continue to look perfectly health with zero signs of illness.

 

[lauraf]

How long have you had the swords? Can you determine if the ones that have died are ones that you bought, or were ones that were born in the tank?

 

[littletankbigworld]

When you clean your tank, don't change the filter carbon unless it is literally falling apart. You can swish it gently in a bucket of old fish tank water. A lot of good bacteria live on the carbon and it's a bad idea to remove it, especially with this many fish deaths occurring. If you must remove the old carbon, place the new carbon and old carbon back-to-back in your filter for a week.

Your best bet is to purchase a liquid nitrate test kit and post the readings. It sounds like a case of high nitrates. How often do you do water changes?

Are you adding any pH chemicals to the water? PH swings can be deadly.

 

[OrangeCones]

pH: 7.2 (My tap is high ph so I buffer to about 7 - 7.5)

What do you do to lower your water's pH?

 

[brian1973]

What do you do to lower your water's pH?

very good question, the more important question IMHO is why are you messing with the PH? The PH out of the tap is fine and you can actually cause more problems adjusting it, and if you insist on adjusting it make sure you are adjusting it before you add it to the tank. Sudden PH changes can cause death, so becareful doing this. Unless you are trying to breed certain species ph is really not that big a deal. the best way i saw it related on this forum was comparing it to humidity for humans.

Just a word of warning on waiting for the carbon bags to be about to fall apart before changing them. Once they come apart carbon goes everywhere and by everywhere I really mean everywhere including getting dumped into the tank then sucked back into the impeller on the filter. I almost destroyed a RENA XP3 canister filter and an aquaclear110 HOB filter when the HOB's carbon bag fell apart. Personally I change my carbon cartridge out about once a month, as long as you have the sponge like pad in the filter or the bio wheels your bacteria load will not be effected enough to cause any issues.

Sorry the reply is so long just wanted to give you as much info as possible.

 

[Kallen]

How long have you had the swords? Can you determine if the ones that have died are ones that you bought, or were ones that were born in the tank?

Honestly, I can't say on an individual level. But I can def say that the majority (if not all) at this point were born/raised in this tank.

When you clean your tank, don't change the filter carbon unless it is literally falling apart. You can swish it gently in a bucket of old fish tank water. A lot of good bacteria live on the carbon and it's a bad idea to remove it, especially with this many fish deaths occurring. If you must remove the old carbon, place the new carbon and old carbon back-to-back in your filter for a week.

Your best bet is to purchase a liquid nitrate test kit and post the readings. It sounds like a case of high nitrates. How often do you do water changes?

Are you adding any pH chemicals to the water? PH swings can be deadly.

Neither of my filters use bags. The Penguin 300 has two small carbon holders that are refillable. The Magnum has a central chamber for carbon. There's no way I can transition old to new. But I do have the foam pad and bio wheels, there I don't believe there is any issue with this. As for nitrate kit, if I don't find mine I will be getting a new one, but since I didn't keep a sample of the old water...

On the mention of the biowheels, how often should those be changed?

What do you do to lower your water's pH?

I use "Proper PH" to buffer it down. More on why to follow...

very good question, the more important question IMHO is why are you messing with the PH? The PH out of the tap is fine and you can actually cause more problems adjusting it, and if you insist on adjusting it make sure you are adjusting it before you add it to the tank. Sudden PH changes can cause death, so becareful doing this. Unless you are trying to breed certain species ph is really not that big a deal. the best way i saw it related on this forum was comparing it to humidity for humans.

Just a word of warning on waiting for the carbon bags to be about to fall apart before changing them. Once they come apart carbon goes everywhere and by everywhere I really mean everywhere including getting dumped into the tank then sucked back into the impeller on the filter. I almost destroyed a RENA XP3 canister filter and an aquaclear110 HOB filter when the HOB's carbon bag fell apart. Personally I change my carbon cartridge out about once a month, as long as you have the sponge like pad in the filter or the bio wheels your bacteria load will not be effected enough to cause any issues.

Sorry the reply is so long just wanted to give you as much info as possible.

I just tested my tap PH and it's higher than my kit can test. My kit has high range that goes as high as 8.8. Judging by the color I'd guess it to 8.9 or 9.0. This is WAY too high for freshwater fish, so I use the above mentioned product to lower it. I keep it at 7.5, which is still on the high side. I add the buffer with the water as it mixes so there are no spikes. Here's a list of prefered pH levels for some common freshwater breeds:

Angelfish 6.5 - 7.0
Clown Loach 6.0 - 6.5
Goldfish 7.0 - 7.5
Harlequin 6.0 - 6.5
Hachetfish 6.0 - 7.0
Neon Tetra 5.8 - 6.2
Plecostomus 5.0 - 7.0
Silver Dollar 6.0 - 7.0
Tiger Barb 6.0 - 6.5
Zebra Danio 6.5 - 7.0

So, 8.9 or even a little higher is too much. I should drop it a little more actually. I have continued this practice for about 6 years, shortly after I got my 90g. Granted, these fish can survive in numbers higher than these, but the higher the level the more discomfort for the fish....

 

[littletankbigworld]

There's your problem. You are killing your fish by adjusting the pH. A high pH is way better than a pH that swings. I have a pH of 8.6 in each tank and my fish are fine. The numbers you gave us for each species are only for if you are breeding them, as someone already mentioned. Stop adding the pH adjuster, do a water change, let the new water sit in a bucket for a little while before adding it, and your fish should be fine.
You still need a nitrate test kit because high nitrates could be contributing to the problem.

 

[Kallen]

There's your problem. You are killing your fish by adjusting the pH.

I'm not arguing your points, but this one I disagree with. I have maintained the same pH for 6 years. There is absolutly no way this caused the death of so many swordtails. I tested the pH when I did the water change (both before and after) and there were no spikes. And even then, IF there had been a spike, I could understand it killing maybe 2 or 3, but only if those 2 or 3 were already stressed. Certainly not 11 of only one species.... These deaths occurred before I did the water change, so there's no way the pH could have spiked anyways.

I will be getting a new nitrate kits in the next couple days when i can get to the store. It kinds irks me that I had one but it's gone missing...

 

[Kallen]

No dead fish today! Had the 3 yesterday....

 

[brian1973]

just the swordtails again? I am honestly out of ideas unless it is simply natural death due to age because since you have been adjusting the PH for 6yrs I personally would rule that out as a possible cause. What about the nitrates?