BikBok Posted September 1, 2009 Report Share Posted September 1, 2009 are paua shells safe to put in freshwater fish tanks. my daughter wants to put a few pieces in her tank (not my preference but it's her tank) so we need to know if it's ok and if it will affect pH. Thanks Quote Link to comment Share on other sites More sharing options...
Caryl Posted September 1, 2009 Report Share Posted September 1, 2009 Shells will raise the pH. Good if you have Africans but not good in a community tank. Perhaps she could line them up in front of the tank, or on top of it instead Quote Link to comment Share on other sites More sharing options...
BikBok Posted September 1, 2009 Author Report Share Posted September 1, 2009 thanks for that. I have a reason to talk her out of it now lol. Quote Link to comment Share on other sites More sharing options...
whetu Posted September 1, 2009 Report Share Posted September 1, 2009 My personal feeling (based on no evidence whatsoever!) is that paua shells may be marginally worse than other shells to put in a freshwater tank. Not only does the outer white stuff dissolve, raising the pH and hardness of the water, but the colourful innner stuff ends up coming off in quite sharp flakes. I deliberately had a paua shell in my tank a few years ago in an attempt to buffer the pH. I thought if I was going to have a shell in there, then it might as well be a pretty one! But as the coloured bit started to flake off I had several mysterious deaths amongst my usually indestructable gold barbs. I suspect they may have swallowed some of the sharp flakes. Like I said, that's only my speculation, and I'm definitely not going to do a controlled experiment to find out if I'm right! Poor little fishies. Quote Link to comment Share on other sites More sharing options...
Aquila Posted September 1, 2009 Report Share Posted September 1, 2009 When I was really young, maybe 9 years old, my dad had a large tank set up with angels. It had a few granite rocks and fake plants and there was a very large paua shell right in the middle of it. None of the fish had health problems (from what I remember) and they grew from wee pups to large colourful adults. Since I was young, I don't know where the shell was brought from (living inland Canada) but it never broke apart even after all those years. Maybe it was from a different tougher species then the NZ paua...or maybe it had some form of protective coating on it. Anyways, if your daughter is really keen on it, maybe you can get a non toxic varnish and coat the shells with several layers to protect them from the elements Quote Link to comment Share on other sites More sharing options...
Cricketman Posted September 1, 2009 Report Share Posted September 1, 2009 a spray of epoxy would seal it and you shouldnt have any problems. and itll make the colours look better! :lol: Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted September 1, 2009 Report Share Posted September 1, 2009 Calcium carbonate is almost insoluble except in acid water. I have three large chunks of marble in one of my tanks without any problems and they have been there for yeers. Quote Link to comment Share on other sites More sharing options...
whetu Posted September 2, 2009 Report Share Posted September 2, 2009 Interesting. My paua shell ended up very, very thin and porous, and some parts of it dissolved completely. Obviously it would depend on how soft and acidic your water was in the first place - but mine was just 'normal' Auckland town supply water. Quote Link to comment Share on other sites More sharing options...
BikBok Posted September 2, 2009 Author Report Share Posted September 2, 2009 our manukau water is pH 7.8 + so i don't need any more alkalinity. She will have to find some other use for the paua pieces.. I might encourage her to do a piece of artwork instead. Quote Link to comment Share on other sites More sharing options...
Ira Posted September 2, 2009 Report Share Posted September 2, 2009 Interesting. My paua shell ended up very, very thin and porous, and some parts of it dissolved completely. Obviously it would depend on how soft and acidic your water was in the first place - but mine was just 'normal' Auckland town supply water. Yup, that's what happens to them in my tanks. I've thrown coral in the filter and a couple pieces of coral in the tank, they don't seem to be dissolving so fast anymore. Quote Link to comment Share on other sites More sharing options...
Aquila Posted September 2, 2009 Report Share Posted September 2, 2009 Now just imagine what will happen to all the diatoms, shelled molluscs and corals if the pH of the ocean keep falling! OCEAN ACIDIFICATION!!! (although its not really turning acidic...just less basic...) Quote Link to comment Share on other sites More sharing options...
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