View Full Version : Panda Corydoras
07-18-2009, 11:19 PM
As of Late i have 3 Panda corys that have been eating algae off the glass which from reading is kinda rare. Now I have added 3 silver dollars to the tank after I had a huge brown algae growth and in 2-4 days it disappeared. I was assuming the corys had been busy but when I took out the silver 5 days later the algae seemed to come back. I left them out to see how the corys would do and they will not eat the algae on the glass when the silver is not present. I put the silver back last night and I checked them after work the next day and they were chomping away at the algae.
Any ideas, thought, random suggestions?
Random article I found on effects of silver and algae http://www.sciencedirect.com (http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T4G-4JRVB2H-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=634e3279bbf543afa5b64ec67d4ccaeb)
07-19-2009, 04:04 AM
Silver is a heavy metal. You're probably poisoning your fish too.
07-20-2009, 06:05 AM
Heh, there is an amazing paper i found on this at http://www.inchem.org (http://www.inchem.org/documents/cicads/cicads/cicad44.htm#6.0) Now from most of the studies and all that I have read they will be fine and the whole algae glass thing is actually connected as to the silver somewhat.
What are the environmental effects of silver in water?
Silver is not a dietary requirement for organisms. It may even be lethal to bacteria, and it inhibits fungi reproduction. This is mainly caused by Ag+ ions. At oral silver uptake by warm-blooded organisms, about 10% is absorbed. Mammal flesh contains approximately 4-24 ppb (dry mass) of silver. Mammals take up silver mainly through plant feed.
Plants may absorb silver, although it has no biological use. Values of between 0.03 and 0.5 ppm (dry mass) were measured in the past. Fungi and green algae may even obtain a silver content of 200 ppm (dry mass).
Soils do not contain great amounts of silver. However, areas rich in minerals may contain higher amounts. In mining areas soil silver amounts of up to 44 ppm were found. In normal air-dried soil concentrations do not exceed 100 ppb.
In water silver and silver compounds are toxic to micro organisms. Fish contain approximately 11 ppm of silver. Silver toxicity to fish is reduced by water. Depending on water hardness, the lethal concentration for freshwater fish lies between 4 and 280 ppm. Freshwater plants tolerate between 30 and 7,500 ppb silver, depending on the species. The lethal concentration for daphnia is approximately 0.25 ppb, and for amphipods at 4,500 ppb.
Naturally occurring silver concentrations in soil and surface water do not normally cause any environmental problems.
LD50 values were determined for various silver compounds. For silver oxide the LD50 for rats at oral intake is 2820 mg/kg, and for silver nitrate the LD50 for mice at oral intake is 50 mg/kg. For dogs 2.3 g of silver nitrate is lethal. Silver difluoride is extremely toxic, and it is also excellently water soluble. Silver toxicity has a very broad spectrum.
Silver is not known to be carcinogenic. However, when it is directly implanted under the skin of animals it can cause cancer.
Now my end problem is the filter bacteria if they are going to get owned and cause a ecosystem collapse hah which is no fun.
07-20-2009, 06:13 AM
Ah fuck, now I remember - Silver also has antibacterial/antisceptic properties, hence it's use in medical instrument in the days before antiseptic wash. I don't know if that plays into this too or not though.
07-20-2009, 06:21 AM
EDIT: Go back and read Part 7.
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