# Why do my snails keep dying?



## Cheltster (13 Jan 2019)

Hello, 

I am after some advice. I have a tank set up since last October. Contains two goldfish and plenty of plants. It's filled with rainwater and there is a 50% water change each week.

Recently I bought three nerite snails that refused to move and I fished them out dead a week later. I then tried a further nerite the other week. This one was active for two days and then suffered the same fate. I also obtained a number of 'pest' snails for free from the same LFS, these were active for a couple of weeks but now I think these have died as well. 

I have no idea what is causing this. The tank is well filtered and maintainence is pretty good. The goldfish are doing fine and there is nothing metal in the tank. Does anyone have any advice?


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## rebel (13 Jan 2019)

Maybe there is a copper contaminated ornament or perhaps the tank has been treated with copper at some stage.


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## Parablennius (13 Jan 2019)

If you're using rainwater it's likely they have no minerals, but I wouldn't expect them to expire so quickly from that. Except that they are most likely more at home with harder water.


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## Cheltster (13 Jan 2019)

Yes I add macros and micros, magnesium and have a bag of oyster grit in the filter to add some minerals. Also I don't suppose low nutrients would cause quick death, more like a long drawn out one. 

The rainwater is collected in a plastic rain butt that I cleaned out at the end of summer. The guttering is all plastic and 18 months old. Roof is all tiles, no felt.


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## Parablennius (13 Jan 2019)

Cheltster said:


> Yes I add macros and micros, magnesium and have a bag of oyster grit in the filter to add some minerals. Also I don't suppose low nutrients would cause quick death, more like a long drawn out one.
> 
> The rainwater is collected in a plastic rain butt that I cleaned out at the end of summer. The guttering is all plastic and 18 months old. Roof is all tiles, no felt.


It won't be lack of minerals then.


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## Cheltster (13 Jan 2019)

rebel said:


> Maybe there is a copper contaminated ornament or perhaps the tank has been treated with copper at some stage.


The tank was new and I cleaned it with just water prior to use. I've never treated it with any medication. The substrate is aquatic compost with black blasting sand on top. 

This is a by product from the production of copper so that could be the source, but I throughly washed it and soaked it prior to use and I know other people often use this as a substrate.


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## dw1305 (13 Jan 2019)

Hi all,





Cheltster said:


> The substrate is aquatic compost with black blasting sand on top. This is a by product from the production of copper so that could be the source, but I throughly washed it and soaked it prior to use and I know other people often use this as a substrate.


The blasting sand would be my guess for the copper source.

About twenty years ago they shot blasted the Clifton suspension bridge, prior to re-painting, and then had to try and remove the blasting sand from the gorge cliff ledges because of worries about zinc and copper pollution.

If you make the water a lot harder it may help by precipitating the copper.

Cheers Darrel


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## Cheltster (13 Jan 2019)

My tap water is as hard as a coffin nail. I'll start switching over to that and see how I get on. 

Might have to try and change the blasting sand out. 

Thanks for the help.


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## Tim Harrison (13 Jan 2019)

Cheltster said:


> The substrate is aquatic compost with black blasting sand on top.


If you know the name of the product you can Google the Safety Data Sheet, and it will give you details of its chemical composition. It'd be interesting to know in what form the copper is present and the percentage, that'd give you a pretty good idea just how toxic it is.


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## alto (13 Jan 2019)

As Tim mentions, but this is really only a selected representative sample, and your particular bag may be more or less representative
- I suspect testing would cost at least as much as replacing with an aquarium marketed substrate

Some years back before the general availability of dark aquarium substrates, black blasting sand was more widely used, and more than a few reported aquariums with livestock toxicity issues
Some of the grit can also be very sharp, especially an issue if ingested or “sifted” by livestock

Of course your snail problem may just be goldfish curiousity - damage to antennae or “foot pad” often leads to snail death ... while smaller fish tend to just irritate, larger fish obviously cause more significant injury, some goldfish completely ignore snails, others harass

Some Nerite snail shipments see significant losses (initially or over several weeks), others experience minimal losses
When selecting at the shop, always choose snails that are clinging strongly to glass (*very* gently remove) or active in the tank, skip any substrate “resting” snails


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## Mihai Varban (25 Feb 2019)

I lost a few nerites after I fixed my gsa issue too well. Did it by dosing phosphates so the nitrates disappeared, repositioning some plants (highlight plants in direct light and low light plants in shade) and feeding less. I think I starved the nerites.


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