15 replies to this topic

[DPFW]

Hi all,
I'm really hoping someone has a suggestion because I'm a bit baffled by a problem I'm having with some new tanks. I'm going to provide a lot of detail so everyone knows exactly what I did, so please bare with me (please note that the timeline may be slightly off because I didn't keep good records).

About 2 years ago 21 tanks (three 20 gallon, eighteen 10 gallon) were bought. They had been sitting in storage until I started using them back in September (I know they were never used before I used them), Before using them I rinsed them out with tap water. I then filled them about half way up with tap water and added water conditioner (API tap water conditioner). Each tank also has a Tetra Whisper in-tank filter (which has a carbon filter and Bio bag). I let the tanks sit and cycle for at least 2 weeks before putting fish in. During that time I also added Seachem Stability Water Conditioner (supposed to prevent "new tank syndrome").

I then added fish (blacknose dace)- I added about 30-40 small (less than 1/4-1/2") fish into each of the 20 gallon tanks. These were all wild caught fish. Before adding them to the tanks I slowly acclimated them to the new conditions over the course of 1-1.5 weeks by doing small (10%) water changes every 1-2 days with the water they would be going into. I never had any deaths during this acclimation time, so I'm confident that the acclimation was done well (or at least not overly stressful). In fact I started to feed after a day or two of putting them in and they were eating well and swimming fine.

After the acclimation was up, I started to partition the fish into the smaller tanks. I put about 3-5 into each of the seventeen 10 gallon tanks. This was back in early October. The fish were fine in most of the tanks- swimming fine, eating fine, etc. However there were about 6-8 tanks where I had a fair amount of death (half or more of the fish would die, although not always right away- sometimes one would die one day and then another would die a week or more later). There were some tanks that definitely seemed to have fish die in it sooner than other tanks though. Sometimes I would add more fish to the tanks that had a lot of death, other times I would not. If I added fish to a tank that had all the fish die I would always do a large (at least 75%) water change and letting that cycle for about a week before adding new fish. If I added fish to a tank that still had fish in it, I would do a smaller (25-50%) water change before adding the new fish.

Here's where it starts to get weird... I had one tank that was perfectly fine crash on me. There had been 5 fish in it for probably a month without any problems and then over the course of 2 days or so all of the fish in the tank died.
I decided at that point to take and clean that tank and 5 others where I was having consistent death (five of these tanks were 10 gallons, the other was a 20 gallon tank). I drained the water completely, bleached the tanks, and let the bleach sit for a few days. I kept the filters running during that time. I then removed the bleach, rinsed the tanks, and set them up like before (new water with conditioner, added the Seachem conditioner, and let cycle without fish for 1-1.5 weeks).
I then added new fish to tanks. Three of the six tanks are now doing fine (two 10 gallons and the one 20 gallon).

Here's the really weird part... The remaining three tanks seem to be killing the fish even faster! I watched several fish (who were looking fine in other 10 gallon tanks) go belly up and die in these tanks within an HOUR of putting them in!!! (I could literally see it happening in front of me)

I really don't know what's going on. If it was the water, I would expect all of the tanks to have had this problem from the onset. I have tested the water and the pH is a little low (around 6) but otherwise I don't see any problems- no nitrates, etc. It seems to me that there is something coming out of these tanks that is killing the fish, but I don't know what it would be or how to get rid of it. And why only 3 tanks out of the whole group of 21??? Does anyone have any ideas?? I'm at a loss here!!!

[Sunfish Catcher 321]

Did you let the bleach sit it could have be left in the three tanks

[NotCousteau]

Sorry to hear about all of the deaths!

Where are you keeping your tanks? Is there something in the air/room that is contaminating your water? It sounds like something bad is getting into your water. Are you accidentally introducing anything that's been sprayed, rubbed or applied to your skin/hands or fish equipment?

[DPFW]

Did you let the bleach sit it could have be left in the three tanks

Yes the bleach sat in the tanks for several days. But then all of the tanks were thoroughly rinsed and refilled. All 6 tanks were done the same way, so I can't see how three tanks would still have bleach in them and the other three wouldn't. Is there a way to test the water for bleach? Maybe I could check that

[DPFW]

Sorry to hear about all of the deaths!

Where are you keeping your tanks? Is there something in the air/room that is contaminating your water? It sounds like something bad is getting into your water. Are you accidentally introducing anything that's been sprayed, rubbed or applied to your skin/hands or fish equipment?

To the best of my knowledge there is nothing getting into the water. There isn't anyone in the room cleaning the tanks/floors/etc. And I, personally, don't apply anything to my hands/skin that could get transferred (I could ask the other person). Unless somehow it's coming in through the air vents (this is one room with two others right next to it).
However, if that was the case wouldn't you expect ALL of the tanks to have deaths? The only time hands enter the water is when we need to take dead fish out of the tank. And if it's coming from the air, all of the tanks would be equally exposed.
However, that being said... any idea what could come in that would cause this? Because if you (or anyone else) has an idea, maybe I would know "what to look for" and how to possibly avoid it...

[smilingfrog]

A few questions just to be sure I am understanding your post correctly. When you mentioned cycling the tanks for 2 weeks, do you mean that you just let the filters run and circulate the water, or did you actually introduce an ammonia source to kick start the nitrogen cycle? Also when you cleaned the tanks with bleach you mentioned letting the filters run. Am I understanding correctly that you ran bleach through the filters? You mentioned the pH being a little low and not having any nitrate, so I am guessing you tested for those, does your test kit also test for ammonia and nitrite? If so were either of these present? I am wondering if ammonia or possibly nitrite may be building up a bit faster in your tanks than your water changes are keeping up with. If you bleached your filter, your nitrogen cycle would be starting from scratch.

[gzeiger]

That was my first thought as well. A 2 week cycle is not long enough to condition a new filter, but it is long enough to kill one that isn't being fed.

There's no convenient test for bleach, but a large overdose of water conditioner should remove it.

The original problem could have been as simple as some fish being larger than others, or the tanks by the door getting more food, adding more ammonia there. What are you feeding? I also suspect that you were going to have some deaths from poor acclimation to prepared foods. Just because of the huge number of fish you started with, you're going to see the full range of individual variation, and some won't adapt well. That's confusing when you also have a real problem and it's confounding the data.

[gzeiger]

On another forum a series of mysterious deaths over several months was found to be caused by a piece of corroding metal that came in with collected rock. That was a saltwater tank which would be more sensitive to chemical changes, but dace are used to flowing clean water and might be sensitive to something like that.

[DPFW]

A few questions just to be sure I am understanding your post correctly. When you mentioned cycling the tanks for 2 weeks, do you mean that you just let the filters run and circulate the water, or did you actually introduce an ammonia source to kick start the nitrogen cycle? Also when you cleaned the tanks with bleach you mentioned letting the filters run. Am I understanding correctly that you ran bleach through the filters? You mentioned the pH being a little low and not having any nitrate, so I am guessing you tested for those, does your test kit also test for ammonia and nitrite? If so were either of these present? I am wondering if ammonia or possibly nitrite may be building up a bit faster in your tanks than your water changes are keeping up with. If you bleached your filter, your nitrogen cycle would be starting from scratch.

Yes, sorry, I should have been more clear about "cycling". I left the filters running and circulate the water and I also added the Seachem (which is supposed to prevent "new tank syndrome" by adding a biological load, although I've always been dubious about how good something like that really is). That's the only ammonia source I used to kickstart the nitrogen cycle.

Yes, I ran the bleach through the filters. I wasn't sure if that was actually the smart thing to do or not, but I did it.

My test kit covered most normal testing things- ammonia, nitrate, nitrites, and pH. I think it also tested phosphates. It's pretty thorough. I don't remember the results because everything was pretty normal (except the pH of about 6).

[DPFW]

That was my first thought as well. A 2 week cycle is not long enough to condition a new filter, but it is long enough to kill one that isn't being fed.

There's no convenient test for bleach, but a large overdose of water conditioner should remove it.

The original problem could have been as simple as some fish being larger than others, or the tanks by the door getting more food, adding more ammonia there. What are you feeding? I also suspect that you were going to have some deaths from poor acclimation to prepared foods. Just because of the huge number of fish you started with, you're going to see the full range of individual variation, and some won't adapt well. That's confusing when you also have a real problem and it's confounding the data.

I hadn't thought to "overdose" on the conditioner to ensure that there was no bleach. I might drain these tanks and rinse them again. It couldn't hurt, I'd imagine (other than wasting time cycling them again).

I do believe that I was overfeeding at first, but I quickly realized that and adjusted. I'm not convinced that I'm overfeeding now (in fact I don't even feed every day). And I don't think that the huge number of fish made a difference because one 20 gallon did absolutely fine and the other did not and they both had roughly the same number of fish in them. And both tanks were established (cycled, etc.) at the same time and in the same way. And they are right next to each other on the rack, so I don't think it's their location (if they were across the room from each other I might agree with that).

Oh, and I'm feeding with frozen Daphnia and frozen brine shrimp. They eat and don't spit it out, so I'm confident that they are eating and taking to the food. And, like I said, if they weren't then I would expect to see a problem in both tanks, not just one.

I feel like there has to be either something leaching into the water from the tank (but why only some tanks when these were all bought at the same time? and why did the bleach "fix" some tanks but not others?). It has to be something pretty severe to cause death in 30-60 minutes of putting a fish in. I can't imagine what that would be. I can't imagine it's biological because that would probably take a longer time to cause death, but if it's not then why did the bleach "fix" some tanks and not others?

Unlike it's, like someone else said, something corroding from those particular filters. The filters are all new and bought at the same time, so I can't imagine why some would corrode and others wouldn't (and what they would be leaching into the water). I'll have to physically inspect the filters. The filters are the only things in the tank, though, so if it's not that then it's something magical wafting through the air and, again, that seems unlikely because then I would think a lot more tanks would be having this problem....

Does anyone else have other thoughts?

[Josh Blaylock]

I really feel like it's Chemical related.

If you have fish dying within 30min of putting them in the tank, that's not long enough for it to be due to ammonia, nitrates, etc... (unless it's crazy high ammonia).

I'd break it down, clean it all again with vinegar and peroxide, rinse it like crazy and try again.

[gzeiger]

I agree with Josh. Then I would also add a quadruple dose of water conditioner, and move the filter pad from an established tank (which will cause the tank to be instantly cycled - the other tank will recover fairly quickly from bacteria remaining on the filter's internal surfaces). Bleach can certainly kill in 30 minutes. Once you have established tanks there should be no need to do 2-week fishless cycles again.

The Seachem product is not intended to be a biological load and will not cycle a tank under the conditions you described. It's advertised as containing the bacteria required to cycle a tank, but if left in an empty tank for two weeks they will all die (even if they survived in the bottle, which is dubious). Many tanks with the fish load you described will cycle acceptably once the fish are introduced, and that is probably what happened here, but you got unlucky on some.

Bleaching a filter will definitely kill all the bacteria and restart the cycle.

[DPFW]

OK, thanks to you both for the extra information. It was very informative and hopefully will help things.

I appreciate the help of everyone who responded. Thanks!!

[Moontanman]

I had a friend with a tank that was set up exactly the way it should have been and every time he would put fish in they would die in a few days to a week or so, drove me nuts trying to figure it out until I asked him where he got an odd looking rock and he said from beside his house. Turned out the exterminators had sprayed his house for termites a few months before. Took out the rock and reset up the tank and it was smooth sailing from there on...

[Mysteryman]

Sometimes the silicone sealer will absorb chemicals and then leach them back out again. Sometimes tanks are made with different types of silicone, giving different results from tank-to-tank.

Sometimes you get bleach up under the plastic rim of the tank, and a little bit drips out again once the tank is refilled, killing the fish.

In either case, rinse very thoroughly, making sure to spray under the rims. Then let the tank sit a week while filled with water, to help leach out anything in the silicone. Then dump out that water and refill, this time adding a heavy dose of dechlorinator.
Rinse out the filters very thoroghly as well.

Let the tanks fun a couple of days before adding the Stability. If the water is bad, it will kill the bacteria and get you nowhere fast, so let it breathe.

After all that you should be fine.

As for Stability, it works great, but the idea is to put in twice what the bottle says on the first dose, let it sit for only one day, and then add the fish. Then add the regular dose daily for the rest of the week, and you're done. I know that's not what it says on the bottle, but those who have used it extensively have learned what works best.
Incidentally, it has DE-nitrifying bacteria in it, too, and this can confuse you when you make your water tests, making you think that your cycle is way off somehow when it's really fine.

Finally, like Moontanman said, your decor items might be to blame. Leave them out next time and see if that helps.

[Sunfish Catcher 321]

I could be right