In article , A. Paul. Ing says...


No the green slime will not harm fish, its algae........The problem if
yu do not have a filter and yu have a fish load that is too much for
the pond setup with quanity of water and plants etc is it can get
toxic with fish waste buildup. Lots of folks have ponds without
filters, and most do not get gin clear water, but they do plant the
pond pretty heavy so they can use the buildup of nutreints from the
fish waste. I have seen folks ponds with high end big bucks filters
look like like a cess pool and I have seen small bodies of water in
full sun without a filter look great. I would aerate the water somehow
though, but given enough shade, and aquatic plants and if the pond is
not overloaded it can thrive just fine without a filter...In that case
I would advise doiung a 25% at least water change weekly or bi monthly
of the ponds water so you do not get a buildup of toic junk from fish
waste. Too much waste from fish also adds to th growth of that green
slime (algae) which in of itself is not bad..its just unsightly to
most ponders who strive for gin clear waters......There is a water way
(actually like a moat) in Japan, that is loaded with
goldfish........no circulation of any kind, no filters, no pumps just
stagnant thick slimey green water in a circular ditch grossly
overlaoded wth goldfish. The fish were placed there by people loooking
to find a place to get rid of their pet fish over the
years........Folks dump popcorn, and allkinds of food into the water,
and those fish in that stagnant green water are the picture of
health......are they happy fish, heck I do not know, and no one else
really does either, but they spawn, they appear healthy and no humans
are intervening on the fishes account since they are doing just
fine......and Japanese people love goldies and koi......

Personally I would buy and use a filter or provide aeration and water
changes at a minimum...and provide shade if needed.


Thank you so much for your very helpful reply.

I'm glad the algae won't harm the fish. I have lots
of plants in the pond (about 60% covered in plants), but
I'll have to think about aerating it though. I've got a
solar powered aerator in my other pond, and that seems
to work well.

The water way in Japan sounds very interesting.
Goldfish must be able to survive just about anything!

I have lots of goldfish, some sort of speckled fish, one
huge black fish and two huge grey-ish fish. So I'm
not very knowledgeable about fish! :-) I don't even know
what they are!


--
***Emma***
http://www.findmadeleine.com/