View Full Version : Excel and dying fish

Lady Hobbs
08-09-2010, 01:12 AM
I wasn't sure where to put this so one of the nice Mods here can move it if they wish. :)

Three days ago I noticed just the start of a bit of BBA on my spiral crypts. I dosed one capful of Excel for 3 days in a row in my 55 gallon. As of tonight, one albino cory died, 2 pracox rainbows and 3 meteor minnows.

This is not the first time I've had an abino go belly up after dosing with Excel but first time it's affected my neon rainbows and minnows. What up with this, ya think?

Everyone else acts just fine.

08-09-2010, 01:23 AM
The first thing that comes to my mind would be possible Oxygen depletion, but that may not be the case. I can honestly say, I've never experienced any fish problems with the use of Excel. Have you used this bottle before?

08-09-2010, 01:31 AM
I also have never experienced any deaths due to excel, even with more sensitive species. I have dosed 2x the amount for a few days in a row and still no problems.

Lady Hobbs
08-09-2010, 01:32 AM
Yes, used it about 3 months ago. I have 3 filters on the tank......a canister, a Cascade HOTB plus a sponge filter I kept running in case I need it in an emergency.

I do have the tank full to the top so perhaps oxygen could have been a problem. So strange that one fish would be affected so much and another not at all. The minnows are top swimmers so you'd think they'd have been nearest to oxygen.

08-09-2010, 02:09 AM
I would doubt O2 depeltion in a topless tank with all that filtration. I have used excel in tanks with the same fish and did not have any issues.

Lady Hobbs
08-09-2010, 02:20 AM
Didn't have a problem with I dosed before so I don't know what's up here.

I did kill a cory before by dumping the Excel on a plant and he was sitting right under it and I didn't see him. Since then, I pour it very slowly right into the filter flow.

Who knows. Maybe just a mystery die off that had nothing to do with the Excel at all.

08-09-2010, 03:03 AM
I dosed excel briefly before I found out it kills elodea. I didn't have any fish deaths then, but my bronze corys did come down with white skin splotches that no-one was able to identify. I stopped the excel, and used melafix, and the spots mostly went away. I don't know if that was related to the excel or not, but the timing was odd.

08-09-2010, 03:05 AM
The parameters all in tact?
I agree, maybe lack of 02. Sorry hobbs for the loss.

08-09-2010, 03:13 AM
Excel is designed as a substitute for Co2 in planted aquariums. Injected Co2 drives down the pH in a tank. Excel does the same thing.

Fast pH changes stresses fish. Stressed fish often die. Too much Co2 or too much Excel can make it difficult for sensitive fish to breath, resulting in suffocation for fish that have higher dissolved Oxygen needs.

Next time you use Excel, Hobbsy, make sure you have larger air stones running in the tank. Will prevent further deaths using that product.


08-09-2010, 03:29 AM
When was the last time you used the excel in that tank?

I noticed that if it hasn't been used for a while in the tank and you add a capful the fish tend to take an adverse effect, i would probably of advised only using half a capful and maybe more air being put in the tank.

Sorry for the loss

08-09-2010, 11:51 AM
I've heard of a few cases of possible Excel related deaths. One was a blatant overdose (1 cap/5g) though. The other case was an african cichlid tank and the excel was used for algae control. Apparently his Ahli went belly up within a few hours of dosing. We largely attributed the death the pH changes caused by the excel.

That said, I dose daily in my 20g and have never had problems.

Lady Hobbs
08-09-2010, 12:08 PM
Thanks everyone. All your comments regarding low oxygen is most likely spot-on. I mean, really. What else could it be? The corys started tearing up to the waters surface almost immediately after dosing. The Minnows and neons rainbows stayed at the top but they probably got the blunt of the dose being at the top as they were.

This reminds me of when my power went off for 5 hours and 4 of my BIG boesemani rainbows died. Nothing else was affected. Some fish just don't react to lower oxygen levels as well as others, apparently.

Thanks to all for comments and suggestions. Air stone will now to added when dosing Excel.

Red! Of course my parameters are fine!! LOL 0/0/5

09-14-2010, 10:54 AM
Glad I saw this topic!!

I was just about to buy some bottles of Excel Flourish. I don't want my fish to die!! Surely 2 caps biweekly would be fine?

Lady Hobbs
09-14-2010, 02:43 PM
My top swimmers and my albino corys all died other than 1. I don't know why these are the only fish that died. My other corys are fine as are my BN. The albino's went one after the other.

I've added an airstone to the tank as recommended by Dave and this could well have been the problem but if I dose the Excel again I will mix it before adding to the tank. I certainly don't understand how people can triple dose.

Excel only lasts about 24 hours. You should be able to dose daily if you wanted.

09-15-2010, 11:52 AM
Adding it close to nightfall, when the lights go out, and the plants start burping Co2 out... could have elevated the levels enough to suffocate the fish.

I think with airpipelines along the sides and back walls will bubble out enough air, plus the filter's surface aggitation.

09-15-2010, 07:51 PM
Lady Hobbs, I may have encountered the same problem. My 72g, which has only recently emerged from an ich outbreak had 3 unexplained deaths in the past few days. The water had been scrubbed of all medication 10 days prior (90% WC, followed a day later by 75% WC, new carbon...you know the drill), ammonia and nitrite were 0, nitrate was >15. I did not test pH when found the dead fish - grr I should have tested for that too! Didn't think for a minute it might have been the Excel though, else I probably would have run more tests.

Since I had replaced all the water I dosed the tank with Excel and Flourish per the instructions for a first time dosing, this was in the evening about 8pm. Lights out at 10, within 36 hours 3 previously healthy fish were belly up. A danio, a Cory and a Betta. But my tank has 2 airstones, 2 canister filters and a spray bar - there is considerable surface agitation - in fact I decided too much so for the Betta and was going to move him, but he died before I could do it.

I am certain that oxygen was not the problem. I thought it might have been the prime, as I had dosed it at about 125% on the last WC, but I have done that in the past with no problem. I lost a lot of fish during my ich episode - none of the dead fish had any signs of ich on them however, but I attributed the deaths to the medicine - but every two days before each new dose of meds I did a WC and added Excel and Flourish.

The bottle of Excel I was using was bought in the last month - how old is your bottle? Maybe we should compare manufacture codes - they might be from the same production run.

I have used Excel for years and never had a problem but there was nothing in that tank that could have been remotely harmful to the fish - the water was pristine, temp was perfect, aeration was massive, I never stick my hands in the tank without washing and rinsing well first so I know there wasn't an unintended chemical in there - and yet three young fish (between 6 months and 1 yr old) that were flourishing one day were belly up the next, not a mark on them, not even any discoloration. Bettas routinely lose color as they decline - but he looked perfect. I wouldn't be too quick to blame this on your tank's oxygen level...if was a combination of Excel and oxygen then my fish would have been fine, but there might be something to the pH thing.

Are you going to use Excel again? I'm not sure I will....

Lady Hobbs
09-16-2010, 10:14 PM
FishGirl.....yes, I have since dosed with Excel but those in the tank were fine with the previous addition just as they are with what I dose now. If I had losses now and then, I would not have pointed in the direction of Excel but one cory died immediately after I dosed and all the others died within hours of dosing. It was only two species.......the albino's corys and the mountain minnows.

I believe when I dosed, it just did not get mixed up into the water fast enough. I now dose right into the filter for instant mixing. I've had no problems with the 29 planted at all.

09-16-2010, 10:43 PM
I dose 2X the suggested amount of Excel on my 100G daily, and my 2.5G betta tank gets about half a cap. No issues, granted all of my tanks are open top very heavily planted and the betta breathes atmospheric air.

I am curious about those of you who experienced losses were your tanks closed top? How heavily planted are the tanks themselves?

I can expect the minnows would have died as a result, they are a cooler water higher current fish which needs higher oxygen demands. The corydoras being a bottom dweller and a hardy catfish I wouldnt have expected to have immediately die from it.

Lady Hobbs
09-17-2010, 12:02 AM
Open top and loaded with plants, Jenn. No problem with the other tanks so I think this goes back to lowered oxygen levels in that one tank. I have since added an airstone.

09-17-2010, 04:16 AM
Closed top, medium plantings- maybe you are on to something about the fish that died being exposed to the undiluted product... I dilute Prime before putting it in, maybe I should do that with Excel too..

09-17-2010, 01:53 PM
I thought excel has no effect on your pH levels, found this on their website in the FAQ section,

Flourish Excel is not carbon dioxide and there is no impact on pH using Flourish Excel

I use excel only in my 75 which is planted and just checked the pH and compared it to all my other tanks and the pH is the same.

Lady Hobbs
09-17-2010, 02:04 PM
Not pH levels but on oxygen levels.

09-17-2010, 02:32 PM
Forgot to include the quote in my post, this is what I was referring to,

Injected Co2 drives down the pH in a tank. Excel does the same thing.

Lady Hobbs
09-20-2010, 01:17 AM

CO2 does drive down the pH just as Dave stated. I thought we had crossed our wires here and CO2 was being confused with pH and the reason for my earlier post. I would assume it would take more CO2 than perhaps we are using but there are articles all over the net about how to control pH using CO2. Here is just one of them but there are many.


Apparently the poster who wrote the last post (deleted due to unnecessary rudeness) has no idea of how many years Dave has been doing this, the articles he has written and published and didn't realize he come across a real expert in his field.

09-20-2010, 02:56 PM
Breaking Dave's post down in parts so I can clarify what I am talking about, I agree 100% on the first part,

Originally Posted by Dave66
Injected Co2 drives down the pH in a tank. Excel does the same thing.

It's the second half that I confused about,

Originally Posted by Dave66
Injected Co2 drives down the pH in a tank. Excel does the same thing.

After seeing this I checked the manufacture website and this is what they say,

Flourish Excel is not carbon dioxide and there is no impact on pH using Flourish Excel.

In my earlier post I stated that I checked my pH levels in all of my tanks and the pH is the same in all of them, This morning I took it a step further and checked the pH in my 75 where I use Excel, the pH is 8.0. I then added my every other day dose of Excel 7.5ml and waited 5 minutes and the pH didn't change, waited another hour and checked again with no changes.

Maybe there is something on their website I'm missing and Excel does have an effect on pH under certain conditions but for me, Flourish Excel doesn't effect pH levels.

09-20-2010, 03:14 PM
That's because your pH is so high and water hard Excel doesn't affect your pH. With the carbonate hardness buffering your pH so strongly, you'd have a heck of a time lowering your pH with anything other than distilled water.