Everything right-fish die, everything wrong-all ok

[MikeSD]

Very frustrating.

I have a 50 gal goldfish tank that has over 60 fish, including 3 pleco and 1 guppie 3 filters and very little maintenance. It's over crowded but fish do fine. Its been up for over 3 months and not a single goldfish has died.

I did an amonia test yesterday and is down in the zero range. Just the lowest yellow color. I figured they had to be swimming in amonia but it hardly registers. I also tedted nitrites and they are zero range too. TDS is 450ish. And Ph is about 7.2ish. Very few water changes. Wierd

However, my 30 gal tank, for which I do frequent water changes, is stable at 7.7ish and TDS in the 150 range is killing my fish. i had a swordtail dye a few days ago. Did a partial water change an 3 more died last night.

I seem to have better luck, when I ignore all the rules The only thing I can thinknof is maybe the water was too warm, that I added. Or had too much dechlorinator added. Can that cause this problem. I onlybremoved about 5 gallons and added 5 gallons. The only change was the water

 

[wystearya]

"t0 gallon" is how much?

I can't say for sure why your fish died, but if you also do infrequent water changes on that tank it could be why. It's best to do weekly large water changes for goldfish.

I'm honestly surprised that your ammonia reading is zero. How old is your test kit?

I'll admit, I am confused by your issue!

 

[MikeSD]

"t0 gallon" is how much?

I can't say for sure why your fish died, but if you also do infrequent water changes on that tank it could be why. It's best to do weekly large water changes for goldfish.

I'm honestly surprised that your ammonia reading is zero. How old is your test kit?

I'll admit, I am confused by your issue!

Sorry, it's 47-50ish.

Test kit is about two weeks from store. I was surprised too with zero. I knd of expected dangerously high. I did about 30% water change anyway.. I'll check it again

To be clear, the goldfish are fine. The ones that died are in the one I maintain properly. Readings are consistent. It's strange. I'm wondering if my water change contributed, since the three fish died right after the water change (about 15%).

 

[Angellove78]

You have 3 filters on the 50g. Everything is reading good. And no fish killed. Sounds like filters work good for that tank. But, your 30g has high nitrate, and when it climbs high little by little, Fish will die if they can't handle it. 5 gallons is not much to lower the levels, so it just keeps climbing. Imo!

 

[Angellove78]

Time to clean the filter. Not just change the pads. I use the old pads when I clean the inside of filters and I only clean them with tank water in a bucket,but never over clean. And don't do a water change when you/ if you clean filters unless readings are high in ammonia. Just sounds like the the filter might be caked more than what it needs to be. Or the bottom of the tank needs a good cleaning. When lowering nitrate levels one must be very careful doing so. Little by little is best, cause fish will go into shock and die from a extreme change. Just something to look into and think about. Check your filter inside first and go from there. Hope this helps. Sorry about the one's you've lost.

 

[MikeSD]

You have 3 filters on the 50g. Everything is reading good. And no fish killed. Sounds like filters work good for that tank. But, your 30g has high nitrate, and when it climbs high little by little, Fish will die if they can't handle it. 5 gallons is not much to lower the levels, so it just keeps climbing. Imo!

I don't know that nitrate is high. I will test tonight. I did test nitrite, and it's low. And my TDS is only a little higher than I started with. It was 37 out of tap and I added a bit of baking soda and it rose to 142. I started at 142 and now it's 150ish. I got one of those TDS meters and gauge when and how much water to change based on rising TDS.

 

[Angellove78]

You might of added a little too much at one time. Messing with ph level with baking soda if not done right will kill fish too. If it was that low and you changed 5g. How much baking soda did you add? Cause you should only add 1 tsp per 5 gallons. And this is suppose to be done very slowly and little at a time.

 

[Angellove78]

And on a side note, some TDS meters are junk, and can't really trust them. Imo!

 

[coralbandit]

I would use a nitrate test and not a TDS meter to know when to change water..
Telling your water is 37TDS out of tap and telling you where ever it lands after you adjust it is the limit of the TDS meter IMO.
It is true that it will show waste in water[look at your g fish TDS] but there can be other factors in a tank that will effect TDS that may not make it the most desirable method..
I love my TDS meter and in a bare bottom tank it could work as a measure of when to change water but in a tank with hard scape I think I would use a nitrate test....

 

[MikeSD]

You might of added a little too much at one time. Messing with ph level with baking soda if not done right will kill fish too. If it was that low and you changed 5g. How much baking soda did you add? Cause you should only add 1 tsp per 5 gallons. And this is suppose to be done very slowly and little at a time.

I'm 100% sure the fish deaths have nothing to do with Ph. I added baking soda when I inotially set the tank up. I have added nothing since thst time. The ONLY change from a week ago was about 15% water change. I did dechlorinate the water. Perhaps that is what killed them. I added the dechlorinator and stirred it up. I added that water after syphining 5 gal out.

So, baring some freak event, I'm thinking it had something to do with
* water temp
* lack of waiting after adding dechlorination solution
* adding too much dechlorination solution
* or all of the above

I repeated the ammonia test, but on my problem tank, to see what it was and this is the result.

Seems to be around 0.25, by the photo but to the eye, in persion, it looks more yellow than green. Definitely not high.

 

[coralbandit]

Many add dechlor right to tank without issue.
5g of any temp water will not change a 30g tank that much.It is a 1/6 change out..You would need to add 'ice water/boiling water' IMO to cause death on such a small water change..
Prime dechlorinator can safely be overdosed 5 times the recommended amount along with many other brands.
Have you tested nitrates yet ?[test your source water also...]

 

[MikeSD]

Many add dechlor right to tank without issue.
5g of any temp water will not change a 30g tank that much.It is a 1/6 change out..You would need to add 'ice water/boiling water' IMO to cause death on such a small water change..
Prime dechlorinator can safely be overdosed 5 times the recommended amount along with many other brands.
Have you tested nitrates yet ?[test your source water also...]

Temp: consistent 77.4 throughout tank

It would seem that nitrates could be the problem but it is strange that i had 25% loss right after changing water. And I do make water changes. Hard to imagine nutrates could be increasing to dangerous levels with only 11 fish in 30 gal with frequent water changes and constant TDS. Could be just an untimely coincidence. I will do a nitrate test tonight, just to be sure.

Thanks to all for suggestions. I will post nitrate test results later

 

[V227]

The weather is warming up. It's not uncommon for water companies to start jacking up Chlorimine levels in the tap. That might be your fish killer. Never heard of a fish OD relating to dechlorinator. Your Goldfish are much more durable to adverse water conditions and are less likely to go belly up as compared to tropical fish.
Double check your dechlorinator, making sure it also detoxifies Chlorimine as well.

 

[MikeSD]

The weather is warming up. It's not uncommon for water companies to start jacking up Chlorimine levels in the tap. That might be your fish killer. Never heard of a fish OD relating to dechlorinator. Your Goldfish are much more durable to adverse water conditions and are less likely to go belly up as compared to tropical fish.
Double check your dechlorinator, making sure it also detoxifies Chlorimine as well.

M dechlorinator says
* removes chlorine and chlorimines
* detoxifies heavy metals
* super sttength

 

[V227]

You know when you deal with tropical fish "It's always something". Most of my stock make it to old age but every once in a while a sudden death occurs. Last month one of my favorite Tiger Stripe Silver Dollar fish jumped and bashed his head on the glass lid. Instantaneous death. A week or two later my baby 2" GT murdered a Buenos Aires and Diamond Tetra all in one day.
I'm sure there is a simple explanation to your aquatic crime scene. There are just too many possibilities and not enough clues.
My 120 gal. Tank maintenence routine: 50% WC each week w/ gravel vac - filter cleaning once every 3 weeks (squeeze out sponges in old tank water) - keep temp 78-82 degrees -
I haven't tested my water parameters in years, and don't even own a test kit.
That's the best advice I can give you. Keep after it, things will level out.