2 fish deaths in 3 weeks

[MarkW19]

Hi guys,

I've just 5 minutes ago lost my second fish in 3 weeks, so I thought it best to ask for some advice.

I had a 10g nano tank, which happily housed an ocellaris clownfish, magenta dottyback, and yellow clown goby, for 2 1/2 years. At the beginning of March this year, I moved house and also "upgraded" to a different tank; the same size, but a bit neater and with a built-in light. My fish survived the 1-hour journey absolutely fine, with the only potential issue being my magenta dottyback whose gills seemed to turn red after the first day, and stayed like that until he died, but other than that he's been just fine. All fish seemed to settle in to the new tank very well.

All of my new tank parameters have been the same as my old tank: 0 ammonia, 0 nitrite, 20-40 nitrates (I know this is high, and I'm trying to reduce it, but I don't have any corals/inverts in the tank), pH 8.2, SG 1.024. The only difference is the tank temp: the tank is in a poorly insulated part of the house at present until we get everything sorted, and has risen from ~25ºc (max 2° swing per day), to ~29.5°c with the recent hot weather we've had over the last couple of months. But, the temperature rises gradually, and never goes more than max 1.5° either side.

The first problem started 3 weeks ago with my clownfish when I was changing the filter media and doing a waterchange. I didn't expect any problems as this was the third time I'd done this exact same thing, which involves gently lifting some of my live rock so I can lift the filter up to replace the media, which inevitably stirs up some debris in the tank. This swirled around for a while and then settled back down when I put my filter back on, as usual. This time, after darting for my fingers in the tank as he has done for almost 3 years, and looking as alert as ever, I noticed him gulping at the surface. This was then followed by some quick "spasms" around the tank, banging into rock etc., lying upside down on the bottom, and then sadly dying. I was incredibly sad about this, as I put so much effort into the tank changeover and journey, and have had these fish in my previous tank, with no problems at all, for close to 3 years. However, I put it down to it "being his time", and possibly him gulping in too much of the "debris" when it was swirling round the tank after I disturbed the rock.

But, today, I was just doing a normal waterchange - not even a filter change, so no debris - as I always have done: SG/temp matched to tank, mixed in a bucket with a powerhead for a minimum of 24hours (this time it was mixing for 3 days), but straight afterwards, I noticed all fish were behaving strangely: both clown gobys (I now have a green clown goby also, which has been in there for a couple of months) were breathing heavily, which has now stopped. But, the main problem was with my dottyback, who straightaway was lying almost on his side at the bottom of the tank, breathing very heavily and with his mouth open. He moved positions approx. 30 mins later, and 20 mins after that, after a couple of spasms, is now dead.

I don't know what I'm doing wrong, other than the nitrates, as ammonia is 0 (I've tested on two kits) and all other levels seem fine. I do have quite a bit of green algae in the tank, which may be consuming a lot of oxygen, and also I understand that higher temperatures can reduce the oxygen level. But, why would both fish die straight after a waterchange? I don't understand.

Hoping for some advice?

[melosu58]

Could be just coincidence as far as after the PWC. Do you have a PH pointed toward the surface for extra aeration. Can you get a water sample to your LFS to get a double check of your water test results.

[David S]

are you using tap water or ro/di water,if your using tap then test it as it is a new water supply.

[MarkW19]

Thanks for the replies guys. I guess that both PWCs could have caused stress in both of the fish, and caused them to succumb to another issue quickly. The filter actually points up from the bottom of the tank to the top, and disrupts the surface quite a bit. I'll take a water sample to my LFS today, thanks for the suggestion.

I use RO (not DI) water, as we have hard water here, but it never measures more than 3ppm (TDS). Both clown gobies seem fine this morning; after 6 years of keeping marines (old nano tank for 2 1/2 years, and the rest in a 40gallon tank, not the same fish though), this is the first time I've had any unexplained deaths like this, as I'm always so careful with everything. It just seems like the PWCs contributed, particularly to the clownfish death as there was so much debris stirred up in the process?

I'll report back what my LFS says.

[Kurt_Nelson]

The first problem started 3 weeks ago with my clownfish when I was changing the filter media and doing a waterchange. I didn't expect any problems as this was the third time I'd done this exact same thing, which involves gently lifting some of my live rock so I can lift the filter up to replace the media, which inevitably stirs up some debris in the tank. This swirled around for a while and then settled back down when I put my filter back on, as usual.

The fact that the fish was gasping immediately after you stirred up some junk sure sounds like ammonia poisoning. I know you said you tested it with two kits, but even so... it just sounds too coincidental.

You have to lift up live rock to change a filter pad? Is this one of those bio-orb tanks?

[MarkW19]

Originally Posted by Kurt_Nelson

The fact that the fish was gasping immediately after you stirred up some junk sure sounds like ammonia poisoning. I know you said you tested it with two kits, but even so... it just sounds too coincidental.

You have to lift up live rock to change a filter pad? Is this one of those bio-orb tanks?

Yes, it's a BiUbe; I wanted a tank that was simpler to maintain as my last nano tank was very fiddly. The live rock unfortunately will only fit on top of a plastic lid on the top of the filter housing. Other than this, it's a tank that's working well for me; I'm doing all maintenance as I always have been, not using their service kits etc.

Could stirring up all that cause ammonia poisoning then? Is it just luck that the other fish weren't affected by this last time?

Also, yesterday I just did a normal waterchange - no filter change - so there was no debris in the tank, and that's when my dottyback died. My other two gobies seem fine and have been acting normally all day.

I dropped a water sample into my LFS today, and am picking it up in the morning.

[MarkW19]

Just got the results back from the water sample I took to my LFS, and ammonia/nitrite are 0, everything else in check, although they didn't test the oxygen level (is this worth me doing?).

My clown dying straight after the waterchange where I stirred up all the gunk would at least be a reason, if that could cause ammonia poisoning/respiratory problems with all the gunk flying around, even if just for 5-10 minutes max. But, it still doesn't explain why my dottyback went straight after the last waterchange, where I didn't stir up any gunk as just did a simple 25% waterchange (no filter change).

I'll keep testing my levels every few days; I'd just love to know exactly what happened though, and if I did anything wrong. It's such a shame as they survived a 1 hour journey in a bag, the changeover to the new tank, and were fine in there for 4 months, and this just came completely out of the blue, as I'd changed the filter twice before as well, with no problems.

I change the filter every few weeks; to minimise any future problems with the gunk (until when/if I find another solution), would it be an idea to put the fish in a bucket for a few minutes while I change the filter, and the gunk settles down afterwards? I know this isn't ideal, but maybe a better solution than them being in the tank at the same time?

[Kurt_Nelson]

Originally Posted by MarkW19

...But, it still doesn't explain why my dottyback went straight after the last waterchange, where I didn't stir up any gunk as just did a simple 25% waterchange (no filter change).

Yeah... that sounds like there's something wrong with your water, doesn't it? You said you matched salinity and temperature, so it seems like we can rule that out. How are you measuring salinity? Refractometer or hydrometer? Hydrometers aren't the most consistent things in the world and having "identical" readings between two containers of water might not be all that identical.

Where are you getting your water? Is it RO/DI or tap?

I change the filter every few weeks; to minimise any future problems with the gunk (until when/if I find another solution), would it be an idea to put the fish in a bucket for a few minutes while I change the filter, and the gunk settles down afterwards? I know this isn't ideal, but maybe a better solution than them being in the tank at the same time?

That seems like it would cause even more stress. Not sure I'd do that...

[MarkW19]

I use a refractometer, and always get the SG either spot on, or max. 0.001 either side. I make my own water using an RO unit (non-DI), and get TDS readings of 2ppm or lower.

Whenever I change the water, I only ever do a max of 25% (often 20%), every 2 weeks; so it just seems odd that my dottyback would die straight after a waterchange (I did the exact same thing I always have done, every 2 weeks, for the past 3 years with him).

I'll take your advice on not doing the bucket thing, and will see if I can find another solution for the filter issue. At least we may have an answer to my clownfish dying after all the gunk, I knew that stirring the gunk up wasn't ideal, but I didn't know it could cause ammonia poisoning, particularly after I'd done the same thing twice before with no problems...

[David S]

when was the last time you changed the membrains in your ro filter,it may also be worth connecting a DI unit inline after your RO unit as well

[MarkW19]

Originally Posted by David S

when was the last time you changed the membrains in your ro filter,it may also be worth connecting a DI unit inline after your RO unit as well

It's a brand new RO unit I've got that's about 4 months old; I usually change the membranes every 6 months, or when the TDS starts increasing, whichever comes sooner. TDS is consistently 2ppm or less on the water I make up.

I've done the exact same routine when doing a waterchange, every 2 weeks, for almost 3 years now (my previous nano tank was the same capacity) - as well as on my previous larger tank for another 3 years before that - and I'm always really careful to match everything as close as possible, so I'd be surprised if it was the new water (my two gobies are fine, 4 days after the last death now).

If stirring gunk up from under the rocks can cause ammonia poisoning, that could explain my clownfish death; but I'm still hoping for an answer for the dottyback death, though, which is the one puzzling me the most, and we were very sad to see him go. He was a character.

I'm scared to death of doing my next waterchange now, which is daft as I've one so many before, without one issue.

[David S]

maybe using a gravel cleaner to remove as much of the gunk as you can during pwc.There must be something under there which is causing the problem

[Kurt_Nelson]

Hmm... doesn't sound like the water is the issue. DI would be better, but 2 TDS out of the RO is pretty darn good. Doesn't seem like that's the problem

Originally Posted by MarkW19

...
If stirring gunk up from under the rocks can cause ammonia poisoning, that could explain my clownfish death; but I'm still hoping for an answer for the dottyback death, though, which is the one puzzling me the most, and we were very sad to see him go. He was a character.

Stirring up stuff could lead to an ammonia spike, but it wouldn't be immediate. It would take a day or two. And I think you said your clownfish went quicker than that. So I probably am leading you down the wrong path on that one. And like you said, that dottyback went immediately after just a water change. Seems like that's an important piece of the puzzle, but the answer isn't jumping out.

I'm guessing the buckets you use for transferring the new water are only used for your fish tank? Are they stored somewhere that they could have been contaminated with some aerosol, or cleaner, or something? And then when you filled them with your saltwater, it got in to your water? Just thinking out loud...

I have two buckets that I use ONLY for new water - old tank water never goes in them. And when they're not being used, they are covered with lids to make sure they aren't contaminated with anything that might be in the air.

I'm scared to death of doing my next waterchange now, which is daft as I've one so many before, without one issue.

I hear ya... but you have to do them. I'm scratching my head on this one with you...

[Edit: OK... I went back and reread your original post. How and where are you storing your saltwater before the water change? In what kind of container? And have you tested the water inside your storage container for ammonia? Seems like we've ruled out the source water, so let's follow the trail to the next possibility. Is it possible that the water is being contaminated by something while it's in storage?]

[MarkW19]

Thanks for all the help guys.

David: I have coral rubble as my substrate (quite big pieces), and siphon as much debris etc. as I can off the rubble whenever I do a water change.

Kurt: Yes, the clownfish showed problems literally 3 minutes after the gunk was stirred up, and within 30 minutes he was dead. The dottyback also went in a similar way, but without the gunk, which is puzzling me the most.

Yes, the buckets I use are used just for my fish tank. They're stored in a closed cupboard which is only used for fish stuff, and there's definitely no aerosol/cleaners etc. that can get in, I'm really picky about stuff like that.

I used to have one bucket marked up "NEW" that I did the same as you with, but I got 2 new buckets a few months ago and have probably been using them interchangeably; but that said, I rigorously clean (plain water, then carefully dry) before/after I use any of them.

I make RO water up and store it in a food-safe water container, that has enough for 2 waterchanges in it (stored no more than a month). I then freshly mix with salt for a minimum of 24 hours. I haven't tested the RO water in the container for ammonia, but...in the case of my clownfish, he actually showed major problems (gasping at the surface, leaning to one side) BEFORE I'd put the new sw in, this happened when I'd removed the old tank water (approx 25%), then stirred up the gunk/changed the filter. I can't remember at what point the dottyback showed problems, but I'll test the water in my container now (I have a bit left) and will report back...

[MarkW19]

Just done the test, Ammonia is 0 in the water container.

[David S]

I think I might be tempted to remove the coral substrate and replace with LS as the substrate you have is a haven for detritus,but only change 25% ish at a time if you do,

[MarkW19]

Originally Posted by David S

I think I might be tempted to remove the coral substrate and replace with LS as the substrate you have is a haven for detritus,but only change 25% ish at a time if you do,

Hi David, unfortunately that's not possible due to the placement of the filter. I've always had live sand in my previous tanks, and would have preferred it for this one. Still, in that regard the only issue is my nitrates which are high (40-50ppm), and PWCs don't seem to reduce them. I've changed onto a different food now which I can control better, so hopefully that will improve the nitrates after a few more PWCs.

[David S]

Good luck

[MarkW19]

Guys, just to give you an update, this is so frustrating, and so odd.

The LFS confirmed that everything was okay in my tank: ammonia, nitrites, SG, pH. I continued to test everything for a few days, and it was all fine, so I decided to purchase some replacement fish. These were a royal gramma, and another small clownfish.

Both acclimatised/settled in fine, and were swimming happily and eating on even the first night. They were absolutely fine for just over 2 weeks, eating great every day, looking very healthy. Tank levels yesterday were also fine.

Then, just two hours ago, I did a waterchange. I did this as I always do, and have done every 2 weeks for almost the past 6 years: mixing the sw for 24 hours to the same SG/temperature as the tank, then doing the waterchange.

I drained the old water out, cleaned the sides of the tank with an algae pad, and then replaced with the new water. Put the filter back on to quickly sort out any floating algae etc. in the tank, and I found that my clownfish was gasping at the surface, breathing very quickly. He's now dead.

My other fish were okay at that point (royal gramma, yellow and green clown gobies), but all of these are now huddled on top of eachother in the same point in the tank (bottom right), breathing extremely heavily, and have been like this for over 40 minutes. It looks like they'll die too.

Again I've tested the SG, pH, ammonia, nitrites, and everything is just perfect. I'm struggling for an answer here; I've kept marine fish for 6 years, and have done so many waterchanges in exactly the same way, without issue.

This is getting soul-destroying, with no answers to anything.

Are there any other tests I should be doing on the new water, to see if there's an issue? This particular RO was 002ppm TDS, SG 1.025 (exactly the same as the tank), and the same temperature (.2°C warmer than the tank).

[melosu58]

I wish I could help you with what`s going on. The only thing I see is after you changed the water. In SW PWC`s are recommended because whole tank changes change the chemisty of the water as to what was and now is. I know when I changed tanks I still used the old water and added new water to try to remain close anyway to what the tank chemistry was. I wonder if this might be what happened the second time around.