> So what I need to do (and I'm sure you'll correct me) is have more plants
> and less fish.
Yes, sorta. If your plants are growing well (and being pruned regularly),
they are actually absorbing the ammonia from the water as fast as the fish
can produce it. This means, basically, that you should have no nitrate
problems in the tank if all other factors (feeding, etc) are in good order.
If the plants are growing well.
There are other things going on that will necessitate regular partial water
changes, so don't skip those. :-)
Also, in my experience, one can have a fair number of fish in an unfiltered,
well-planted tank. I had several "natural" aquariums when I lived in
Arizona -- all outside -- that had thriving plant populations in them. They
also had fairly heavy fish loads (akin to what one might find in a
moderately populated tank w/ filtration), were probably overfed, and
received less than perfectly-scheduled maintenance. :-0 The fish did quite
well, believe it or not, and would've been amazing had I adhered to a
more-regular water changing routine. ;-) My most-crowded, least
water-changed, *happiest* aquarium of the lot was a bare-bottomed 20 gallon
"long" (30"L) that contained a pupfish and a profusion of feral mollies that
I had collected in NV (and wouldn't let Peter stomp on). It was
"beautifully" decorated with some java moss burried under mats of hair
algae, and topped off with a smattering of tropical hornwort (yes, really!).
I topped off the tank when it evaporated to halfway down, water changed it
about every month *or three*, and removed nitrogenous wastes by yanking out
handfulls of hair algae when I needed to harvest some Java moss for my other
tanks. ;-) Ask Peter: it was pretty amazing how well those fish did on such
terrible neglect!
Rhonda Wilson, also of AZ, has a whole fishroom full of unfiltered planted
tanks (the quietest fishroom you could ever imagine, as there are no
filters/pumps to break the silence). She has very nice fish, and can keep a
larger population of critters per gallon than you would expect. Of, course,
she is much better on the water changes than I was then. ;-)
My point, after all this rambling, is that you can keep more fish than you
think in this tank if you plant it and the plants are well taken care of
(light, water changes, etc). Use easy to grow plants, and if you can, ones
that grow rapidly so that you can remove some of the nitrogen products from
the tank (via pruning and thinning) on a regular basis. I have never used
CO2 on any of these tanks, nor did I fertilize other than feeding the fish.
An iron additive in the substrate might help, and you *will* need good
lighting (2 watts/gallon or a bit more). That done, you will find that you
probably can stock it almost as if it were a conventional filtered tank...
but not overstock it, as we all tend to do in said filtered tanks. ;-)
> Also are there plants that would do a better job than others
Hair algae works great, but is probably not as attractive as one might like.
;-) I think anything that grows quickly, necessitating frequent
thinning/pruning, should work well, such as floating plants, Hygros and many
other bunch plants, Vallisnerias, and water sprite. Also, Lee Newman, of
Vancouver, BC, Canada, uses terrestrials (eg: houseplants) growing emersed
in his filters to great effect. He loves things like Geophagus and
Satanoperca spp (South American Eartheaters), which are real buggers when it
comes to H2OQ -- worse even that Discus. He says the roots of these plants
pull out amazing amounts of nitrogenous waste and are easier for him to keep
in these setups -- "Geos" dig and like very soft, very warm H2O which plants
don't enjoy. Whatever grows best for you is probably your best bet, even
Java Moss. :-)
Julie <><