Post water change fish death

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fatboy8

Piranha
MFK Member
Mar 9, 2012
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Philadelphia
Just did a weekly 50% WC to my 65 gallon tank lost a Denison barb and a lemon Barb. The lone clown loach, filament Barb, and silver dat seem off while the SA bumble cats all look fine. Only thing I did differently this week was waited about 10 minutes after filling the tank back up to dose with Prime. I also completed a 50% weekly water change to my 20 gallon tank with nothing significant noted.

Am I to blame for waiting to dose the prime for their death? I was wondering if maybe water chemistry changed but the 20 gallon gas had no effects the 65 had.
 
Yes one should always use dechlorinator prior to refilling their tank, and not after. Chlorine/chloramine are toxic to fish.
 
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Yeah just got caught up with the other tank removing a sponge filter. Hate to see it. Real shame to see. I’ve forgotten once or twice but never had these results.

I’m really surprised with a clown loaches sensitivty it survived.
 
Consider chlorine gas was used to kill humans in WWI, where it burned lungs and asphyxiated soldiers on the battlefield, then consider what it can do to sensitive gill membranes in the confines of the average aquarium.
 
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Consider chlorine gas was used to kill humans in WWI, where it burned lungs and asphyxiated soldiers on the battlefield, then consider what it can do to sensitive gill membranes in the confines of the average aquarium.

Yeah watched it first hand dumb mistake on my part. Tough to watch it go down. All over my mind being on my other tank.
 
Tough lesson for sure.

I've posted the following a number of times over the years.

Both chlorine &/or chloramine can cause long term damage & even death to fish, in some cases even at low levels, especially young fish which are typically the most sensitive to these substances. Free chlorine can cause acute necrosis of gill tissue in fish, the younger the fish the worse it can be. Chlorine also has the potential to wipe out most/all of the bio bacteria in your system. In short chlorine is an oxidizer, that can burn a fishes gills & kill cell tissue, sometimes even at low levels.



The amount of chlorine and or chloramine can vary greatly from one municipality to another, as well as from one tap to another, and can also vary greatly throughout the season. There is no way that anyone on a public forum can possibly attempt to tell you what a "safe" amount is in your case unless they have the specs on your local tap water at your user end. Water temp, pH values, etc can also determine how 'safe' certain levels of known toxic substances can be on fish.



According to Edward Noga, a professor at NC State that is considered an expert in the disease & health of fish, chlorine levels as low as 0.10 mg/l (which is common in many tap water levels) can be accutely fatal in aquaria that has low levels of organics. (as in a new set up) Others have found residual chlorine levels as low as 0.05 mg/l to be toxic to certain species of fish.



There has been a TON of work done in this area over the past few decades, by a number of researchers, such as Tompkins & Tsai (1976) for anyone that is interested in understanding just how toxic both chlorine & chloramine can be in a closed system that contains fish.



The fact that your fish haven't died is positive, but that in no way means that the exposure hasn't caused damage to your fish. Again, this will be dependant on numerous factors, and can vary greatly from one hobbyists situation to another. What may be safe for some people, could prove to be a disaster for the next person a few cities or towns over.



Unfortunately the LC50 (survival time) of most tropical species of fish placed under various levels of chlorine/chloramine has yet to be established, but the bottom line is both substances are highly toxic to most aquatic organisms.



From the EPA ....



http://www.epa.gov/chemfact/s_chlori.txt



V. ENVIRONMENTAL EFFECTS

A. Toxicity to Aquatic Organisms

Chlorine has high acute toxicity to aquatic organisms; many toxicity
values are less than or equal to 1 mg/L. Twenty-four-hour LC50
values range from 0.076 to 0.16 mg/L for Daphnia magna (water flea)
and from 0.005 to 0.1 mg/L for Daphnia pulex (cladocern)
(AQUIRE 1994); 48-hour LC50 values range from 5.3 to 12.8 mg/L for
Nitocra spinipes (snail); and 96-hour LC50 values range from 0.13
to 0.29 mg/L for Oncorhynchus mykiss (rainbow trout), from 0.1 to
0.18 mg/L for Salvelinus fontinalis (brook trout), and from
0.71-0.82 mg/L for Lepomis cyanellus (green sunfish) (AQUIRE 1994).
Papillomas of the oral cavity in fish have been associated
with exposure to chlorinated water supplies (NTP 1992).

Low level chlorination (0.05 to 0.15 mg/L) results in significant
shifts in the species composition of marine phytoplankton
communities (HSDB 1994).
 
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