JeffinMS wrote:
20 gal tank with tetras, 2 black molly's, one orange molly, clown loaches,
few others and a large pleco.

I have 4 or 5 medium sized shells in there, one is used as a home by the
pleco.

I have one live plant which grows pretty wildly (long). I cant remember what
it is its been so long since i bought it. I have one artificial weed patch
(That flat thing they say is for fry to hide in).

I did have one longer plastic plant but took it out because it seemed to be
taking up too much room and the fish seemed like they were avoiding it and
tryting to swim around it.

I'm not much of a plastic plant person. With real plants, prey fish
like tetras will often hover at the edge of the plant or swim nearby.
They dart in if they feel threatened.

How much vegetation should I have..generally? And what about shells and
places for fish to hide, etc.

In your tank, maybe three medium sized plants as cover for the mollies
and tetras. Add a couple of piles of driftwood, rocks, or shells
arranged to make fish-sized caves or hiding places for the pleco and
loaches. Leave the spawning grass if you like babies, although they'll
have a hard time escaping the loaches.

You can add more cover, of course. Fish don't mind swimming through a
jungle of live plants and loaches love caves.

Is it a bad idea to change the environment slightly to increase the area the
fish have to swim and move around?

Community fish like yours don't seem to mind occasional redecoration.
You might stress the loaches if you did something silly like moved their
cave every day.

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