Update and more questions

[FishNoob]

Update: haven't lost any fish in over a week, and all the various
tests are showing exactly what they should in a healthy tank. All the
fish look good, and the three molly fry are visibly growing.

So time for a new set of questions, I think :-)

First, the fry - how fast do they grow? How long does it take for a
molly to get to full-size?

Second, airstones - we got a small pump with an airstone attached.
Should it be running all the time, or just a few hours a day, or
what? Best placement in the tank? The only advice I found on websites
was to position it near the back of the tank, on the opposite side to
the filter - anything else I need to think about? Is it best under
the gravel or on top of it?

--
FishNoob

[NetMax]

"FishNoob" > wrote in message
...
> Update: haven't lost any fish in over a week, and all the various
> tests are showing exactly what they should in a healthy tank. All the
> fish look good, and the three molly fry are visibly growing.

:o)

> So time for a new set of questions, I think :-)

Almost any question you can think of has been asked, so the FAQs and the
google archives are good resources if you find the responses here are not
providing enough info, or are not timely. Just FYI, since I noticed that
this post didn't get a reply.

> First, the fry - how fast do they grow? How long does it take for a
> molly to get to full-size?

I've never really paid attention, so breeders would be best to answer
you. Generally, fry cannot be moved for about 3 months. Adult size
would probably be in the neighborhood of 9 months, but full size might
take years. Note that their growth rate is *significantly* affected by
the amount and type of foods given, interval between meals, and the
temperature of the water (to just name a few variables). It's possible
to artificially (or through significant manipulation) cause them to grow
quite large very quickly (this is a normal activity in fish farming), so
unlike mammals, knowing their age does not determine size (or
vice-versa).

> Second, airstones - we got a small pump with an airstone attached.
> Should it be running all the time, or just a few hours a day, or
> what?

Actually not an easy question to anser because of the many perspectives.
From the perspective of noise to fish, it should be left on 24/7. Fish
then program the sound into white noise (like us), and cease to really
hear the thundering sound that it makes underwater. From the perspcetive
of noise to people, many turn them off when sleeping (if the tank is in
their sleeping area). From the perspective of re-oxygenation and
turbulence, it depends on whether the airstone's action is significant to
these two factors. If the tank was over-stocked, very warm, heavily
planted, had sick fish etc, then 24/7 would be a good idea. If
understocked, lightly planted, healthy fish etc, then why add an
airstone?

> Best placement in the tank? The only advice I found on websites
> was to position it near the back of the tank, on the opposite side to
> the filter - anything else I need to think about? Is it best under
> the gravel or on top of it?

Entirely up to you. The bubbles can cavitate inside a filter's impeller
well, so this can be a problem, though many filters will tolerate a small
amount of air bubbles without difficulty, so ymmv. When I use airstones,
I like to have the bubbles surface at the point of water entry from a
filter (causing them to shoot across the surface). This maximizes the
surface tension breakup. If going for turbulence, then set the airstones
lower in the tank, however the lower the airstone, the more powerful the
airpump must be to counteract the pressure of the water. If you find the
air flow inadequate with a new set-up, lift the airstone up higher.

Placing the airstone under the gravel simply causes some of the
airbubbles to combine, so you have less but larger bubbles. Maximum
gaseous exchange underwater is achieved with the smallest size air
bubbles (greatest surface area and contact time), and maximum turbulence
is achieved with larger bubbles (....if it makes any difference to you -
I can be a wealth of trivia ;~).
--
www.NetMax.tk

> --
> FishNoob