i have a fish bowl for the past 1 month. it is fairly large, can fill
approx 3.5 gallons. i have a single male betta fish in the bowl, we
have a heater for the temperature. Me and my family are quite
frustrated with the absolute inactivity of this betta fish, it mostly
comes up near the top and hangs around the air bubbles (there is a
water plant). is it possible to say add maybe 2 guppy fish in this fish
bowl. we are not interested in a fish tank and would like to keep the
bowl only.

would like to know from you people if it will be possible to add 2
guppies (of the same sex) to our current setup without any undesirable
results. or if the guppies are not a good idea then any other fish
which could help us out of our predicament.

First of all, this is not normal behavior for a betta. They usually are
quite responsive to activity outside their bowl and will greet anyone who
comes by with the "betta dance" even if the visitor doesn't feed him. If
your betta is languid he might be ill. However, if he's blowing bubble nests
this is a good thing; male bettas make bubble nests when they're happy. Is
your heater set to about 78F? That would be about right for a betta; they
can be quite inactive if the water is 74F or cooler. If the water is warm
try showing the betta his reflection in a mirror for a few moments each day;
that might jolt him out of the doldrums.

Second, male bettas are solitary fish. Some will do OK with small tankmates
such as neon tetras, ghost shrimp, or snails but many will not. My own
experience is that many of my bettas developed quite an appetite for snail
and/or shrimp but got on well with neon tetras while others preferred to
have the tank to themselves. Don't put in anything with large flashy fins
that look too much like a male betta (like fancy guppies or mollies) or
other fish known to be fin-nippers (like barbs or tetras) or there will be
trouble. If you really want to add some fish I would try a couple of small
neon tetras first. Bettas and neons generally just ignore each other, and
even if the betta flares at them on occasion the neons can easily scoot
away. However if you are going to put a few neons in with the betta 3.5
gallons is probably too small. If you really want to see active bettas get a
10-gallon, put a mesh divider down the middle, and put a male on each side;
bettas often thrive when they have a "flare buddy" with which they can
interact. Give each one a nice broad-leaf plant and some cover so they can
avoid one another if they wish.

--
John Goulden
mostly guppies, goldies, bettas, and swordtails