Esha Gastropex (Copper Sulphate) toxicity in soft water

[Hufsa]

I originally wrote this in the Gastropex shrimp thread but I think it actually fits better in its own thread now.

Ive tried on two occasions now to use Esha Gastropex in my tank.
First time I used the full day 1 dose, and immediately my fish started acting super off. Boraras were shoaling tightly, pygmy corys as well, and all the corys were shooting to the surface for air very frequently. Both these groups of fish dont normally shoal like this in my tank. Otos, Sturisoma etc looked somewhat unhappy.
Since they had such a strong reaction to the medication I immediately performed a 80% water change and added extra dechlorinator in the new water.
Even though the tank was only medicated for 10 minutes, I saw an immediate die-off of a large number of rhabdocoela worms, and some (but not all) limpet snails also died.
I thought the fishes reaction was pretty weird and decided to give the tank a few days to rest and see from there.
Today I tried the second time with half the dose, since I still had a few surviving limpets.
Immediately the same reaction from fish. This time I observed for a little while to see if the fish would settle down,
but pulled the plug on it at 30 minutes. Another 80% water change and fish are mostly back to normal, besides some faster breathing.

There is a single neo shrimp in the tank (hes not supposed to be there), he did not appear visibly affected. But I suppose the fish have a lot more body language.

Ive been thinking about this all day, and after some quick googling it appears copper toxicity varies greatly with differing water hardness?
I have quite soft water compared to you guys in the UK, and I wonder if this is the reason for the reaction.
The pamphlet doesnt say a single thing about water hardness or adjusting the dose.

I want to know exactly which concentration of Copper i am adding to my tank, so I can compare with the scientific research that has been done.

1 ml of Gastropex contains 24 mg Copper Sulphate.
The online pamphlet states that 20 drops = 1 ml.
The first day full dose is 36 drops for my tank.
What concentration of copper am I adding to my 180 liter tank?


[Edit]:
I got some help from a friend and from what we can make out the concentration in my tank would be 0.06 ppm Cu or 0.24 ppm CuSO4

Calculations:
1 ml / 20 drops = 0.05 ml per drop
0.05 ml per drop * 36 drops = 1.8 ml
24 mg Copper Sulphate * 1.8 ml = 43.2 mg CuSO4 in my full dose for 180 liter.
To get mg/L and ppm we divide 43.2 mg / 180 liter, giving us 0.24 mg/L CuSO4 (and ppm).
I put this number into the rotalabutterfly calculator to get the pure Cu value as well, which is 0.06 ppm

Looking at this paper from the University of Washington, they tested various species of fish in varying water parameters.
My water has a pH of about 7.1, 3 dKH and 6 dGH.
It seems this study puts the most emphasis on KH / Alkalinity.
If alkalinity is the deciding factor then the "Moderately Hard" test water is closest to my water; pH 7.8, 60 Alkalinity (3.3 dKH) and 90 Hardness (5.4 dGH).

From what I understand the LC50 value is how many ppm CuSO4 it takes to kill 50% of the fish within 48 hours.

The most sensitive species was the rainbow trout.
LC50 of CuSO4 in "Moderately Hard" water for this species is 0.06 ppm CuSO4, aka over four times less than one dose of Gastopex
I feel it makes the most sense to use this species as an analog for my relatively sensitive softwater fish. Most are from south america where metals would be in very low concentrations.
The NOEC (No Observed Effect Concentration) is 0.03 ppm CuSO4.
So its possible that for my inhabitants the dose of Gastropex I should use is closer to 1/8th of the normal dose

For comparison, koi had a LC50 of 0.99 ppm and NOEC of 0.06 ppm.
This would suggest only 1/4th of a dose is safe for koi


Seeing all this research put so much emphasis on alkalinity when dosing Copper Sulphate, my mind boggles a bit when I see that Gastropex doesnt have any instructions to adjust the dose at all..

 

[sparkyweasel]

I got some help from a friend and from what we can make out the concentration in my tank would be 0.06 ppm Cu or 0.24 ppm CuSO4

I concur.

I put this number into the rotalabutterfly calculator to get the pure Cu value as well, which is 0.06 ppm

If Gastropex is made with 24mg/l of hydrous CuSO4. If it's anhydrous it would be 0.096ppm.
Did you get the 24mg/l figure from a reliable source? Esha seem to be very secretive about what's in their products.

Copper is known to be more toxic to fish in soft water, I can't find a detailed reference at the moment, but t is mentioned in general terms in the Interpet Manual of Fish Health, which is generally well-regarded.
hth

 

[Hufsa]

Did you get the 24mg/l figure from a reliable source? Esha seem to be very secretive about what's in their products.

I contacted Esha by email and got the info from a sales and communication manager
"1 ml contains;
Copper Sulphate 24 mg
Proflavine hemisulphate 0.2 mg"

 

[sparkyweasel]

That should be right then.
I've had a look at Dieter Untergasser's Handbook of Fish Diseases. He says "Copper toxicty may occur in treatments with copper sulfate if the water hardness is not at least 10°DH."
The therapeutic dose he recommends is 1 - 1.5mg/l Cu, but warns that the water "must be hardened to at least 10°DH" before treatment.
hth

 

[Oldguy]

copper toxicity varies greatly with differing water hardness?

"Copper toxicity may occur in treatments with copper sulfate if the water hardness is not at least 10°DH."

Some thoughts, no evidence or any experience with your product.

I think its to do with pH and hardness. Both are combined in natural waters. Greater hardness and higher pH (pH still in the range for fish) the less soluble the copper becomes, tends to precipitate out as the carbonate. Found a school field trip trying to find copper pollution in a limestone stream at Ecton Copper Mine in Staffordshire in the UK, test kits were showing negative despite copper colouration on some the mine spoil in the area. Its just a thought and of cause their test kits could have been poor.

In UK tap water pH is raised and phosphates added, especially in soft water areas to reduce leeching of plumbing metals into household water supplies. (main concern is lead, upto about 1965 lead pipes from water company stoptap to the household was still the practice in the UK as still are copper pipes in the house.

 

[Simon Cole]

@Hufsa I did the same calculations as you a few years ago. I read all the studies that you did, plus a few, and came to the conclusion that it is harmful and ineffective. You are not going mad, science is science, fact is fact, and most EHSA products are useful for killing stuff. I just think it is an awful way to treat livestock.