I have been hanging out with the goldfish people on another group (I
have one goldfish tank) and they are always talking about using sand
or no substrate at all to get rid of all that messy stuff on the
bottom of the tank. Having read that good bacteria live in the
substrate I got to thinking about whether in general that crud is
really good or bad, specially in a planted tank. Is it just "soil in
the making"? Or is it "nasty pollution"? I must admit it looks
horrible when I vacuum the gravel, specially when I come across a bit
of food that has fallen down between the gravel where the fish can't
get it and has gone moldy.

On the other hand, I have had a small plastic tank going since last
summer with no filtration or maintenace whatsoever that has pond
water, snails, plants and lots of tiny pond creatures. Obviously some
kind of balance has been worked out there. The snails make lots of
dropping but maybe the plants and tiny creatures use them as food?

I'd love to hear what you knowledgeable people think. I've only been
keeping fish for less than a year.

Judy
http://jumaka.com/aquarium

There's crud and there's crud. A certain amount of detritus (mulm) is
acceptable, even desirable, especially in a planted tank. But if you don't
want tons of uneaten fish food rotting in the gravel. And most people vacuum
the gravel of unplanted tanks, to keep the substrate from going bad.

You don't have to do this with a planted tank. The plants will keep the
substrate from going bad, by absorbing the mulm and bringing oxygen into the
gravel.

A lot of people keep goldfish in bare-bottom tanks. Goldfish are really pond
fish. They are big, do best in schools, and produce a lot of waste. Often,
people are only keeping them indoors for the winter. Water quality can be a
real problem in an aquarium, and it's hard to keep plants with goldfish: they
eat them.

So I guess my answer is that it probably is good for goldfish, but that doesn't
mean it's good for every tank.


Leigh

http://www.fortunecity.com/lavender/halloween/881/