03-17-2007, 07:49 AM
| || | It can be done. Do not collect the first water from the gutter as it may have washed away rat urine, bird droppings and any other unwanted things. If you live in the rural areas, the risk of contamination from pollutants is rather low. You will have to run the rainwater under filtration with carbon to remove any more unwanted things.
Originally Posted by fish_4_all
I could be totally misunderstanding this though because I have I have not heard of the practice. I have used rain water in the past for my indoor plants when I could cleanly collect it but I really don't think it is good for the fish. If filtered someway then maybe.
Urban areas may be out of the question as there are a lot of pollutants involved and the rainwater won't be safe for the fish anymore. Note that rainwater often lacks buffering capacity so you'll need to check your KH before using a CO2 unit. KH lower than 4.5 will simply risk your tank to pH crashes thus killing or harming the fish.
Goldfish are rather tolerant of most water conditions so I wouldn't assume straight away that your other fish will be fine. There are fish that you will need to avoid if you wish to use rainwater. Rift Valley cichlids in particularly have to be avoided unless you try to increase the KH and pH to certain levels that will allow them to thrive well.