Koi-lo wrote:

Get an aquarium sponge (those made for the Aquaclears are ideal), snip a
small hole in one end and pull it over your filter's intake strainer. Make
sure to cover the whole "strainer" part. Some of these filters for larger
tanks have a suction strong enough to actually trap and kill smaller fish.
I have them on all my filter intakes to prevent accidents and torn fins.

So far it's only an issue with Dart and one of the filters from the
10g (a temporary situation until the bacteria spreads to the new
filter). But it's a good idea... Actually, the larger filters (only
one on for now, until it's got bacteria, then the 2 filters from the
10g go off and the second large filter goes on) have mid-tube as well
as end-of-tube intakes, I think the sponges would be esp. good for the
mid-tube intakes - I'll do what you suggest before I open these back
up (they're adjustable and closed now) as these will generate more
suction than any other intake. And I've already got a sponge for the
bottom of one of the large filters (the substrate is sand and they say
the sponge will help keep sand out of the filter and extend the life
of moving parts). So, I guess it's just a question of whether I put a
sponge on the temp filter - I'll see what I've got around at home -
easier than dealing with torn fins...

It sounds like he's really enjoying himself. :-)

My husband thinks the surfing is intentional, I'm not sure all of it
is, but there are definitely times when I think he decides to "coast"
to his intended destination. :-) I was very surprised that he wasn't
bothered more by the current (given the volume of "bettas can't handle
current" statements out there), but it doesn't seem to bother him
hardly at all (guess the filter in the 6g helped get him used to a
current, so he's now prepared for a slightly stronger current).

I once had a community betta who learned to sneak up on the other fish -
then rush attack them an rip their fins. :-() All my bettas now live
alone.

Yes, he's already discovered that he can hide in the stump decoration
and "pop" out of the holes suddenly - so we're watching this to be
sure everyone else learns to watch out for him as fast as he figures
out better ways to stalk... If I ever see an injury, he'll go back
into isolation.

Keep us posted.

As of this morning, everyone was present and accounted for, no
injuries, though Dart was looking very shark-like as he patrolled the
waters. :-)

Do you think more fish would increase or decrease his aggression?

My plan is:

Add 5 cory cats (with some bio-spira) once the new filter has some
bacteria going (basically, as soon as we get time to go to the fish
store again). These guys will help get food that finds its way to the
bottom.

After they're adjusted, add 1 rasbora (giving a total of 6 each).

Then later, maybe, depending on the nitrate levels these fish create,
3 more otos (for a total of 5).

And that's it - I want a light load and I'm hoping the above will be a
light load for a 50g (which I'm now realizing is a lie on the part of
the sticker on the tank - this thing probably only holds about 40g
:-/ (Oh well, my fault for not considering this *before* I filled it
with fish g)).

Liz