# Excel did not kill my bristlenose plecos- I killed them using Excel!!!



## wetworks (Jul 22, 2011)

I started to get a problem with algae in my Fluval Edge over the last few weeks. This morning before I left the house I dosed the tank with Excel, and when I came home both my albino bristlenose plecos are dead!!!I just did exhaustive testing on the water, and all parameters are normal- no ammonia registers, and very little nitrate, everything else is fine:
Nitrite: 0
pH: 7.1
KH: 2
GH 12
temp: 78 F
The only conclusion that I can come to is that the Excel is responsible for their death. It is extremely unlikely that they would both die the same day of 'natural causes'. I had these two plecos for almost 2 years, so I am pretty bummed. Confused, too, because none of my shrimps (RCS and CRS, + one bamboo shrimp) are dead.


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## Mostlydave (Jan 12, 2012)

I feel for you, after my initial dose of excel per the instructions on the bottle I had some fish die, and I like you can think of no other reason besides the excel. I lost 6 of 7 ember tetras 2 glofish and a black skirt tetra. My ghost shrimp were not harmed by it. Nothing is wrong with my water and I think it was the excel.

I dosed for a 55g tank but I have 80 pounds of gravel so I guess I might have overdosed it. I have been using it every other day since then and my fish seem to be okay now.

my lfs hasn't gotten any ember tetras for a long time either so I feel bad for my lone survivor (the smallest on coincidentally)


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## TWINSCREWED (Nov 21, 2011)

Hey Mostlydave Msjinkzd a forum sponsor and a real pleasure to deal with has ember tetras. u should checkout her sponsor forum. Heck looks like she could be your neighbor well at least she's in Pa. lol


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## Mostlydave (Jan 12, 2012)

Thanks for the head up, looks like I might get some replacement embers!

Anyone else have any thought for wetworks and my own problem with excel killing fish? does everyone here dose based on tank size or acutal water in tank taking gravel etc. into account?


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## houseofcards (Mar 21, 2009)

First off sorry for the loss!

I've said this many times, that excel is a very dangerous product to use, especially in small tanks. It is very easy to overdose to a point that can kill fish. How much did you actually dose?


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## garfieldnfish (Sep 25, 2010)

I have a bottle of that stuff sitting around. I bought it for plants a long time ago and forgot I had it. Now I will throw it out. Fish poop will have to do for my tanks.


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## wetworks (Jul 22, 2011)

houseofcards said:


> First off sorry for the loss!
> 
> I've said this many times, that excel is a very dangerous product to use, especially in small tanks. It is very easy to overdose to a point that can kill fish. How much did you actually dose?


I dosed 6 ml. Instructions say amount for a 6 gallon is 3 ml, and I dosed double per instructions I found on this and other sites for algae removal.


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## wetworks (Jul 22, 2011)

garfieldnfish said:


> I have a bottle of that stuff sitting around. I bought it for plants a long time ago and forgot I had it. Now I will throw it out. Fish poop will have to do for my tanks.


I have had this same bottle for about 6 months, never used the stuff much. Now I wish I had thrown it away.


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## mistergreen (Dec 9, 2006)

I've killed a few fish by double dosing the initial dose.

I believe it binds to O2, so your fish suffocates. Some are more sensitive to this than others.


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## houseofcards (Mar 21, 2009)

wetworks said:


> I dosed 6 ml. Instructions say amount for a 6 gallon is 3 ml, and I dosed double per instructions I found on this and other sites for algae removal.


You doubled up on the initial dose on excel. 6ml in a 6g, that is a pretty big dose and many fish will take issue with it. Don't feel too bad, it's happened to me when I used it on a small nano. 

The product is not marketed as an algaecide so your taking your chances when you OD it.


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## wetworks (Jul 22, 2011)

houseofcards said:


> You doubled up on the initial dose on excel. 6ml in a 6g, that is a pretty big dose and many fish will take issue with it. Don't feel too bad, it's happened to me when I used it on a small nano.
> 
> The product is not marketed as an algaecide so your taking your chances when you OD it.


Yeah- I pays my money and I takes my chances. I had previously used it in a 30g and a 38g to successfully remove algae with no ill effects to any fauna- but it did make my crypts melt, and when the leaves re-grew they were sort of stunted looking. Now I know.


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## LB79 (Nov 18, 2011)

I believe on the instruction panel it says not to overdose in bold letters. I underdose and everyone's fine. You never know what they'll put in a liquid carbon solution...


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## VeeSe (Apr 16, 2011)

The initial dose is already a huge step up from the normal dosing, and you doubled up on it? I wouldn't be surprised to see it kill fish, as it plainly gives the warning for overdosing there. When people talk about double dosing etc, they mean 2x of the 5mL per 50 gallons or 1mL per 10 gallons , not the initial dose... so double dosing in your tank would be 1.2 mL of Excel since the standard dose is 0.6 mL. The initial dose is already a shock at 5x, but I think you effectively 10x dosed your tank by doubling that amount. When I used Excel in my tank, I skipped the initial dose and just started with the normal doses. Never had any issue and seemed to get a bit of positive response from the plants.

As houseofcards said, I feel like it was a HUGE risk to dose 6mL into a 6G tank. I have never even dosed that much in my 55G before. That being said, I'm sorry that you lost fish and that's really unfortunate =( but I don't think Excel is a terrible product as long as directions are followed.


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## forester (Mar 12, 2010)

VeeSe said:


> The initial dose is already a huge step up from the normal dosing, and you doubled up on it? I wouldn't be surprised to see it kill fish, as it plainly gives the warning for overdosing there. When people talk about double dosing etc, they mean 2x of the 5mL per 50 gallons or 1mL per 10 gallons , not the initial dose... so double dosing in your tank would be 1.2 mL of Excel since the standard dose is 0.6 mL. The initial dose is already a shock at 5x, but I think you effectively 10x dosed your tank by doubling that amount. When I used Excel in my tank, I skipped the initial dose and just started with the normal doses. Never had any issue and seemed to get a bit of positive response from the plants.
> 
> As houseofcards said, I feel like it was a HUGE risk to dose 6mL into a 6G tank. I have never even dosed that much in my 55G before. That being said, I'm sorry that you lost fish and that's really unfortunate =( but I don't think Excel is a terrible product as long as directions are followed.


i agree , i have have never used excel though as an algeacide , only used it as a little help to go with the DIY yeast CO2 , everyother day , normal dose of 25 mL (capful ) for 50G on my 58G , always seemed to help out a bit ^^ but i will say i had 3 fish die after an initial dose of excel to a tank when i did a a little rescaping and 50% water change . only time i ever used that initial dose on tank ....but i replaced alot of water too


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## TWA (Jan 30, 2012)

A ml per gallon is a pretty big dose. You dosed enough for like, a 55 gallon tank on a nano..


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## Chlorophile (Aug 2, 2011)

I would advise against double dosing the initial dose. Double dosing the daily dose is probably not as bad. 
The initial dose is already an overdose so to speak.
I wonder if anything in excel evaporates? Maybe it can become more concentrated over time because I had some shrimp deaths due to excel dosing once I neared the very bottom of the bottle.


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## nalu86 (Oct 19, 2010)

1ml per 10 gallons is the dose!! or every water change 5ml per 10 gallon, not 2ml per 1 gallon.
offcourse you killed your fish...


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## wetworks (Jul 22, 2011)

I get it, I get it. I have never really used Excel for the intended purpose- I only had it for a week before I got my pressurized CO2, so I have only used it to get rid of algae. I dosed using the same method (doubling the initial dose) to get rid of hair algae in my 30g, with no trouble, so I figured that it would be OK in the 6g. I guess I should change the heading of this thread to read: *I KILLED MY FISH USING EXCEL*.

I pulled all my shrimps and plants out of that tank last night, shortly after my first post. This morning I was really glad I did. My lights just came on at 8AM and I cannot see into the tank past about 3 inches. All of my livestock is OK- I got them into my QT just in time I think.


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## demonr6 (Mar 14, 2011)

That sucks, I use it all the time in my nano and never had an issue. Maybe my bettas are more tolerant. Probably a good idea to back off using it in my coffee too..


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## wetworks (Jul 22, 2011)

VeeSe said:


> The initial dose is already a huge step up from the normal dosing, and you doubled up on it? I wouldn't be surprised to see it kill fish, as it plainly gives the warning for overdosing there. When people talk about double dosing etc, they mean 2x of the 5mL per 50 gallons or 1mL per 10 gallons , not the initial dose... so double dosing in your tank would be 1.2 mL of Excel since the standard dose is 0.6 mL. The initial dose is already a shock at 5x, but I think you effectively 10x dosed your tank by doubling that amount. When I used Excel in my tank, I skipped the initial dose and just started with the normal doses. Never had any issue and seemed to get a bit of positive response from the plants.
> 
> As houseofcards said, I feel like it was a HUGE risk to dose 6mL into a 6G tank. I have never even dosed that much in my 55G before. That being said, I'm sorry that you lost fish and that's really unfortunate =( but I don't think Excel is a terrible product as long as directions are followed.


A lot of people have never had any trouble with Excel, and I am not in any way trying to bash their product. I never used Excel as a carbon source, only occasionally used it for algae treatment, and I never had trouble dosing 2x initial in my other tanks so I assumed (wrongly) that my results in bigger tanks would be the same in a smaller tank as long as the ratio of ml to gallons was the same. I did not think it was a risk at the time, but today I certainly know it was a risk.


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## wetworks (Jul 22, 2011)

demonr6 said:


> That sucks, I use it all the time in my nano and never had an issue. Maybe my bettas are more tolerant. Probably a good idea to back off using it in my coffee too..


I find it has a bitter taste, kind of like Equal or some other artificial sweetener. Or cyanide. :hihi:


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## VeeSe (Apr 16, 2011)

wetworks said:


> A lot of people have never had any trouble with Excel, and I am not in any way trying to bash their product. I never used Excel as a carbon source, only occasionally used it for algae treatment, and I never had trouble dosing 2x initial in my other tanks so I assumed (wrongly) that my results in bigger tanks would be the same in a smaller tank as long as the ratio of ml to gallons was the same. I did not think it was a risk at the time, but today I certainly know it was a risk.


Hey, we all live and learn. This is certainly not the worst thing that could happen.


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## xenxes (Dec 22, 2011)

I use a 1/2 dose once a week in my tanks :/ Learned my lesson too, think it caused a few oto deaths early on.


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## cott (May 26, 2007)

Excel killed all my mountain minnows and my albino coreys as well and I dosed according to directions. I will not overdose with this stuff ever.


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## wetworks (Jul 22, 2011)

I have no plans on using it for any reason at any dose in the future. Even if it is my fault (this time) I have already had enough bad experience to know I don't want to use it. Pressurized CO2 for everyone!


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## mistergreen (Dec 9, 2006)

You can kill fish with pressurized CO2 too 
If you add too much that is. I've done that too.


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## Seattle_Aquarist (Jun 15, 2008)

H wetworks,

First, I am sorry for your loss. When treating an aquarium for an algae outbreak I dose glutaraldehyde mixed to Excel strength of 1.5% concentration. I do not double the 'Initial Dose', only the 'Daily Dose' amounts. I find the Excel/glut has minimal effect on GSA and GDA but it can be effective on the 'hair type' algae.


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## nalu86 (Oct 19, 2010)

I dosed metricide full strength between 10-15 ml to a 125 gallon tank and it killed all my BBA  Its nice and red now  It also keeps my green algae on my glass under control. 
Be carefull with it, I dose every day 1 ml to my 10 gallon.


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## Naekuh (Oct 19, 2011)

mistergreen said:


> You can kill fish with pressurized CO2 too
> If you add too much that is. I've done that too.


Ditto!

ive killed all my fish minus 1 betta, because he took air... by injecting too much co2...


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## FishFarmer (Feb 8, 2007)

This is an interesting topic. I have not had good luck with keeping my pleco's and otos alive in my planted tank for more than about 4 months--and the Excel could have been the issue (I use API CO2 Booster). I had three otos which all died within 4 months. Then I got two pitbull plecos and one died the very next day, and the other about 3 months later. I think some fish are more sensitive to the chemical than others; I have 10 neons, 6 black phantom tetras, 2 angels, and 6 cories and they are all doing fine (knock on wood).

For the record I dose 5mL in my 29 gallon (recommended dose is 1mL/10 gallons, so I'm a little over).


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## BIG_Z (Dec 7, 2011)

I have been playing with excel overdoses and have yet to kill any fish. I might have luck on my side but have yet to execute any fish (other than already sick and or weak fish with it) You mentioned bristle noses, I have a tank that has 4 albinos in it that has made it all the way up to 8X dose (I got scared and backed of at that point)..the initial dose is what kills dont mess with that..as long as you work up to a dose slowly you will be fine


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## xenxes (Dec 22, 2011)

Naekuh said:


> Ditto!
> 
> ive killed all my fish minus 1 betta, because he took air... by injecting too much co2...


Too much CO2 can also cause a nitrobacter slow down / die off and lead to a nitrite spike. Nothing in excess  Just enough CO2 and fert to keep up with the light. Unless you're using 10 hours of direct sun each day you should always be under the recommended dose.


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## papwalker (Feb 22, 2013)

*Sometimes Excel kills fish.*

Excel can kill fish even in normal doses. Like everything else, it's a numbers game. 
It depends on the O2 available in the tank. It's a reducing agent and may even react with other compounds to further reduce O2 availability.

If the O2 levels are marginal then the fish may die over a few hours. Because the level of O2 is so variable for so many reasons, some aquarists have no issues at all whilst others have tragedy.

I have used it and have had mixed results in this regard.
Never use it and leave the tank. Watch the fish closely or add the excel to a noisy water change to be safe.

If you're quick, adding more agitation or a 'noisy' water change can save them.


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## d2creative (Jan 24, 2013)

nalu86 said:


> 1ml per 10 gallons is the dose!! or every water change 5ml per 10 gallon, not 2ml per 1 gallon.
> offcourse you killed your fish...


I thought I saw a post from seachem reps that said .3ml per gallon??
I've been dosing 1.2ml daily in my 4g betta nano.


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## CrypticLifeStyle (Jan 16, 2013)

Awesome topic/thread. This is why I stopped using it myself after it killed one of my GEOS a month ago. $60- beauty queen. I feel everyone's Pain in here. Stuff like this is what prevents me from ever going high tech. I love my fish more then plants


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## ThatGuyWithTheFish (Apr 29, 2012)

xenxes said:


> Too much CO2 can also cause a nitrobacter slow down / die off and lead to a nitrite spike. Nothing in excess  Just enough CO2 and fert to keep up with the light. Unless you're using 10 hours of direct sun each day you should always be under the recommended dose.


Fish will probably suffocate before the bacteria dies.


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## wicca27 (May 3, 2009)

um wait a minut am i the only one that sees something a tad off here? why did you have 2 adult bristlenose plecos in a 6 gallon aquarium? a tank that size is barly big enough for 1 adult seeing how they get up to 4 inches long.


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## iant (Feb 13, 2013)

LB79 said:


> I believe on the instruction panel it says not to overdose in bold letters. I underdose and everyone's fine. You never know what they'll put in a liquid carbon solution...


Here's what's in liquid carbon from one of our guru from my previous post:

Glutaraldehyde is a colorless liquid with a pungent odor used to sterilize medical and dental equipment. It is also used for industrial water treatment and as a chemical preservative. However, it is toxic, causing severe eye, nose, throat and lung irritation, along with headaches, drowsiness and dizziness.

Glutaraldehyde is an oily liquid at room temperature (density 1.06 g/mL), and miscible with water, alcohol, and benzene. It is used as a tissue fixative in electron microscopy. *It is employed as an embalming* fluid, is a component of leather tanning solutions, and occurs as an intermediate in the production of certain industrial chemicals. Glutaraldehyde is frequently used in biochemistry applications as an amine-reactive homobifunctional crosslinker. The oligomeric state of proteins can be examined through this application.

Monomeric glutaraldehyde can polymerize by aldol condensation reaction yielding alpha,beta-unsaturated poly-glutaraldehyde. This reaction usually occurs at alkaline pH values.

Uses
A glutaraldehyde solution of 0.1% to 1.0% concentration may be used for system disinfection and as a preservative for long term storage.

Glutaraldehyde is used in biological electron microscopy as a fixative. It kills cells quickly by crosslinking their proteins and is usually employed alone or mixed with formaldehyde as the first of two fixative processes to stabilize specimens such as bacteria, plant material, and human cells. A second fixative procedure uses osmium tetroxide to crosslink and stabilise cell and organelle membrane lipids. Fixation is usually followed by dehydration of the tissue in ethanol or acetone, followed by embedment in an epoxy resin or acrylic resin.

Glutaraldehyde is also used in SDS-PAGE to fix proteins and peptides prior to staining. Typically, a gel is treated with a 5% solution for approximately one half hour, after which it must be thoroughly washed to remove the yellow stain brought about by reacting with free tris.

A polymerized isomer of glutaraldehyde trademarked as polycycloglutaracetal by Seachem Laboratories, Inc. is the active ingredient in a product called Flourish Excel, a fertilizer for aquatic plants. It is claimed that it provides a bioavailable source of carbon for higher plants that is not available to algae. Though not marketed as such due to federal regulations, the biocidal effect of glutaraldehyde kills most algae at concentrations of 0.5 - 5.0 ppm. These levels are not harmful to most aquatic fauna and flora. Adverse reactions have been observed by some aquarists at these concentrations in some aquatic mosses, liverworts, and vascular plants.[citation needed]

Check out the msds for it. This is info I got from someone who works at seachem. I researched it due a bad rash I got from some of my excel getting on my hand.


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## Magnum26 (Feb 25, 2013)

Sorry for your loss I've dosed tanks before (twice) and ended up killing 90% of my tank because I got the dosage wrong.


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## Hilde (May 19, 2008)

The plecos are sensitive to excel or cidex. Thus you have to dose less than suggested. I found this out the hard way. Cory's to I found are sensitive to it.


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## wkndracer (Mar 14, 2009)

iant said:


> Here's what's in liquid carbon from one of our guru from my previous post:
> 
> *****
> A polymerized isomer of glutaraldehyde trademarked as polycycloglutaracetal by Seachem Laboratories, Inc. is the active ingredient in a product called Flourish Excel, a fertilizer for aquatic plants. It is claimed that it provides a bioavailable source of carbon for higher plants that is not available to algae. Though not marketed as such due to federal regulations, the biocidal effect of glutaraldehyde kills most algae at concentrations of 0.5 - 5.0 ppm. These levels are not harmful to most aquatic fauna and flora. Adverse reactions have been observed by some aquarists at these concentrations in some aquatic mosses, liverworts, and vascular plants.[citation needed]
> ...


This has been entered by someone and it's taken directly from Wikipedia but I believe it to be bogus.
Seachem Laboratories Q&A promotes it too but doesn't state in any 'fact' they ever received patent for any proprietary chemical blend. 
trademark = simply a name ref. "Monster" or lovely words that say what exactly?

*polymerized isomer of glutaraldehyde trademarked as polycycloglutaracetal by Seachem Laboratories *
a link to that being stated as fact not fiction would be appreciated. *Caveat emptor*


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## CoffeeLove (Oct 31, 2012)

Ive been putting two capfulls of excel in my 40b without any losses. Weird.

I also keep a airstone in my tank 24/7 to keep surface scum away

---
I give my fish coffee


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## Tetranerd (Oct 26, 2012)

I use 12 ml of Metricide daily in my 90 gal tank without adverse effects to my 3 albino BN plecos, my emerald cories or the multiple tetras & angels in my tank. 1 ml per 10 gal, not per gal. I'm sorry for your loss.

Sent from my DROID X2 using Tapatalk 2


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