Ardan
10-03-2004, 08:34 AM
Chlorine/Sodium Hypochlorite (bleach) use and its toxicity to fish by Ardan October 2, 2004
This article is written after a personal terrible experience of mine. It is not written for sympathy or any other reason than to share my experience so that you may learn from it and hopefully avoid such an experience.
I needed to clean my fill hose system as there was a bad odor coming from it after one year of use for water changes. Potossium Permanganate solution was used 4 times through the hose and did not get rid of the odor. The hose is the clear vinyl type used for potable water. I have it hooked to a pvc system with a pump from my water barrels.
I was concerned that a bacteria was growing in the fill system.
I mixed 2 cups of bleach in 5 gallons of water, pumped it through the fill system, let it sit 10 minutes, then flushed the system 4 times with tap water, then once more with tap water plus a large amount of dechlorinator to neutralize any residual chlorine.
1.Evidently I was wrong and a residual amount of bleach was left in the piping or hoses
2. At the same time, unknown to me, the city water department added more than normal chlorine to the water supply (normal at this time of year) (usual amounts were .2 ppm on my test kit. the day after my experience, I measured 1.5 ppm on my test kit in the tap water and the water smelled of strong chlorine
3. the aeration in my water barrel was not as strong as usual (the bubbling was weaker, probably due to an aging airstone)
Anyway, early Sunday Morning, September 19, 2004, I did the usual 50% water change on my 2 discus tanks (one 50 gallon, one 75 gallon) containing 19 discus, some adults, some 1 year old, and went outside. When I came back in 1 and 1/2 hours later, some of my discus were hanging at the surface, some were laying on the bottom and all had rapid gill movements. Slime coat was being shed and hanging on to the fish. Discoloration was occurring. I knew immediately it was a water problem due to the recent water change in relation to the rapid onset of symptoms. I smelled the water and detected a moderate smell of chlorine (not strong enough to detect without really smelling for it). I did not take the time to test the levels in the tank.
I immediately added a large amount of dechlor to the tanks and began massive water changes with dechlorinated water (one 50%, then one 90%, then another 75%) I then added salt at 2 tblsp/10 gal. Also added Hydrogen Peroxide (H2O2) to give extra oxygen to the tank, and increased the aeration in the tank.
Some of the fish started to swim a bit and I thought some might make it. I left to get groceries and when I returned all were dead.
It was more difficult to accept than I ever thought losing them would be, but I will get more discus, maybe next year and I will learn from this experience and do things a bit different. I think I will use dechlorinator routinely as a precaution. I will monitor aeration in the water barrels more closely. I think I will still need to use bleach for cleaning, but I think drying after using bleach is very important (I did not dry my fill lines after the bleach use)
I had a hard time writing this and had only confided in Carol Roberts and Al (Brewmaster)about my experience. Al is a very good friend and wonderful person and offered to help me get started again right away, but I have a stubborn streak and will wait until finances and work are better. I really appreciate his support and this website. He goes way above and beyond the average person in helping people. Carol is a great person too and had had a similar experience with bleach, but caught it within 10 minutes and saved her fish. I appreciate learning from her experiences.
These discus were all discus purchased from Cary at GLD, so you can imagine how beautiful they were. I was quite attached to some of them due to there beauty and character. I regret that I had no recent pictures of them when they were healthy.
I did take some pictures of the symptoms but as of yet I have not been able to look at them or share them.
Anyway I write this article to share what I have learned.
Chlorine and or bleach (sodium hypochlorite) is a great disinfectant and cleaning agent for aquariums and equipment. It is an oxidizer. It is also an irritant to skin and mucous membranes, especially the respiratory tract. Use good ventilation when using and wear protective rubber gloves to prevent skin contact. Wear protective eye glasses.
Sodium hypochlorite (bleach) is a form of chlorine.
After using bleach for cleaning, adequate rinsing is necessary to remove all traces of bleach. Air drying after rinsing is recommended.
When fish are exposed to chlorine it irritates their gills and skin. The protective slime coat is stripped exposing the bare skin to the chlorine resulting in skin burns.
The longer the exposure, the more severe are the reactions. As the gills are irritated, oxygen is not able to reach the blood.
Chlorine destroys cell proteins and enzyme systems.
The toxicity of chlorine increases at lower ph and higher temperatures. (as in discus tanks)
SIgns and Symptoms
The fish are hanging near the surface of the water, trying to get air and to get out of the contaminated water. Gill movement is rapid.
Some fish dart around the tank.
Fish begin to lay on the bottom of the tank and do not move as oxygen is depleted from their system. The fish do not swim much either due to the lack of oxygen.
Slime coat is being shed and long strands of slime cling to the body. Burn marks appear as spots or discoloration on the body.
Treatment
1. Get the fish to fresh dechlorinated water either by transfering the fish. or
2. Use dechlorinators to neutralize the chlorine
3.massive water changes, using dechlorinated water. Time is of the essence, the sooner this is caught the better the chances of saving the fish.
4. Increase aeration.
Toxicity
1ppm chlorine is toxic to all fish, whereas as little as .4 ppm is toxic to game fish. (per safety data sheet by Sechelle Ltd of London) (see the box labeled "ecological information" on the web page) http://cgi.www.sechelle.co.uk/data%20sheets/sodium_hyper_safety_sheet.htm
.2mg/l kills most fish rapidly according to A to Z of Tropical Fish Diseases and Health Problems by Burgess, Bailey and Excell
References
http://cgi.www.sechelle.co.uk/data%20sheets/sodium_hyper_safety_sheet.htm
A to Z of Tropical Fish Diseases and Health Problems by Burgess, Bailey and Excell
This article is written after a personal terrible experience of mine. It is not written for sympathy or any other reason than to share my experience so that you may learn from it and hopefully avoid such an experience.
I needed to clean my fill hose system as there was a bad odor coming from it after one year of use for water changes. Potossium Permanganate solution was used 4 times through the hose and did not get rid of the odor. The hose is the clear vinyl type used for potable water. I have it hooked to a pvc system with a pump from my water barrels.
I was concerned that a bacteria was growing in the fill system.
I mixed 2 cups of bleach in 5 gallons of water, pumped it through the fill system, let it sit 10 minutes, then flushed the system 4 times with tap water, then once more with tap water plus a large amount of dechlorinator to neutralize any residual chlorine.
1.Evidently I was wrong and a residual amount of bleach was left in the piping or hoses
2. At the same time, unknown to me, the city water department added more than normal chlorine to the water supply (normal at this time of year) (usual amounts were .2 ppm on my test kit. the day after my experience, I measured 1.5 ppm on my test kit in the tap water and the water smelled of strong chlorine
3. the aeration in my water barrel was not as strong as usual (the bubbling was weaker, probably due to an aging airstone)
Anyway, early Sunday Morning, September 19, 2004, I did the usual 50% water change on my 2 discus tanks (one 50 gallon, one 75 gallon) containing 19 discus, some adults, some 1 year old, and went outside. When I came back in 1 and 1/2 hours later, some of my discus were hanging at the surface, some were laying on the bottom and all had rapid gill movements. Slime coat was being shed and hanging on to the fish. Discoloration was occurring. I knew immediately it was a water problem due to the recent water change in relation to the rapid onset of symptoms. I smelled the water and detected a moderate smell of chlorine (not strong enough to detect without really smelling for it). I did not take the time to test the levels in the tank.
I immediately added a large amount of dechlor to the tanks and began massive water changes with dechlorinated water (one 50%, then one 90%, then another 75%) I then added salt at 2 tblsp/10 gal. Also added Hydrogen Peroxide (H2O2) to give extra oxygen to the tank, and increased the aeration in the tank.
Some of the fish started to swim a bit and I thought some might make it. I left to get groceries and when I returned all were dead.
It was more difficult to accept than I ever thought losing them would be, but I will get more discus, maybe next year and I will learn from this experience and do things a bit different. I think I will use dechlorinator routinely as a precaution. I will monitor aeration in the water barrels more closely. I think I will still need to use bleach for cleaning, but I think drying after using bleach is very important (I did not dry my fill lines after the bleach use)
I had a hard time writing this and had only confided in Carol Roberts and Al (Brewmaster)about my experience. Al is a very good friend and wonderful person and offered to help me get started again right away, but I have a stubborn streak and will wait until finances and work are better. I really appreciate his support and this website. He goes way above and beyond the average person in helping people. Carol is a great person too and had had a similar experience with bleach, but caught it within 10 minutes and saved her fish. I appreciate learning from her experiences.
These discus were all discus purchased from Cary at GLD, so you can imagine how beautiful they were. I was quite attached to some of them due to there beauty and character. I regret that I had no recent pictures of them when they were healthy.
I did take some pictures of the symptoms but as of yet I have not been able to look at them or share them.
Anyway I write this article to share what I have learned.
Chlorine and or bleach (sodium hypochlorite) is a great disinfectant and cleaning agent for aquariums and equipment. It is an oxidizer. It is also an irritant to skin and mucous membranes, especially the respiratory tract. Use good ventilation when using and wear protective rubber gloves to prevent skin contact. Wear protective eye glasses.
Sodium hypochlorite (bleach) is a form of chlorine.
After using bleach for cleaning, adequate rinsing is necessary to remove all traces of bleach. Air drying after rinsing is recommended.
When fish are exposed to chlorine it irritates their gills and skin. The protective slime coat is stripped exposing the bare skin to the chlorine resulting in skin burns.
The longer the exposure, the more severe are the reactions. As the gills are irritated, oxygen is not able to reach the blood.
Chlorine destroys cell proteins and enzyme systems.
The toxicity of chlorine increases at lower ph and higher temperatures. (as in discus tanks)
SIgns and Symptoms
The fish are hanging near the surface of the water, trying to get air and to get out of the contaminated water. Gill movement is rapid.
Some fish dart around the tank.
Fish begin to lay on the bottom of the tank and do not move as oxygen is depleted from their system. The fish do not swim much either due to the lack of oxygen.
Slime coat is being shed and long strands of slime cling to the body. Burn marks appear as spots or discoloration on the body.
Treatment
1. Get the fish to fresh dechlorinated water either by transfering the fish. or
2. Use dechlorinators to neutralize the chlorine
3.massive water changes, using dechlorinated water. Time is of the essence, the sooner this is caught the better the chances of saving the fish.
4. Increase aeration.
Toxicity
1ppm chlorine is toxic to all fish, whereas as little as .4 ppm is toxic to game fish. (per safety data sheet by Sechelle Ltd of London) (see the box labeled "ecological information" on the web page) http://cgi.www.sechelle.co.uk/data%20sheets/sodium_hyper_safety_sheet.htm
.2mg/l kills most fish rapidly according to A to Z of Tropical Fish Diseases and Health Problems by Burgess, Bailey and Excell
References
http://cgi.www.sechelle.co.uk/data%20sheets/sodium_hyper_safety_sheet.htm
A to Z of Tropical Fish Diseases and Health Problems by Burgess, Bailey and Excell