Yep thats the automatic tranny dipstick  :)    try turning slightly as you
pull on it

I don't 'think' there is a drain plug in the automatic transmission ( I'm
not sure since
I've only owned manuals ( 5 spd ). You may have to drop the 'pan' on the
tranny
and drain that way ( good idea btw .....   you can clean the sludge/ build
up out
of the pan and replace the filter while you are in there )

I dont know of ANY automatic transmissions that have drain plugs...always
wondered why???

You have to pull the pan. while you are there change the filter. The pan is
the one that says metric on it. You will anso need a pan gasket. Get those
before you start

You WILL get dirty in this task
Make sure when you remove the pan to LOOSEN all the bolts then start
removing them from ONE SIDE ONLY!!. Put the drain pan under that side as you
remove the bolts and it makes the least amount of mess. Once the pan is
drained enough to remove you can remove the rest of the bolts and dump the
remaining fluid in the drain pan

Remove the filter at this time and replace, it should be fairly
straightforward on how it comes off and goes back on

Remove all the gasket material from the pan and transmission or it will leak
when you put it back together. A paint scraper works well for this but be
careful not to gouge either surface or it will leak also. If you have
problems getting the gasket off there are solutions you can get to help
remove the old gasket. Once it is clean (both surfaces) put the gasket on
the pan so the holes line up and hold in place with two bolts and mount to
the transmission. Don't tighten the bolts until all the bolts are in
otherwise some of the gasket holes might not line up and it will
leak...Notice I keep mentioning that it will leak. I stress this because its
important to do it right so you don't have problems later down the road.
Tighten all your bolts and you are now ready to add fluid.

Reposted, hit the wrong send button (sorry labtech_one)

As far as the dipstick goes if it is stuck you can try twisting it but you
can also remove the entire tube. There should be one bolt mounting the tube
to the motor and it seals to the transmission with an o-ring. You may have
some luck getting the dipstick out that way if it is really stuck. Worse
case you replace the whole tube which you should be able to match up at a
local salvage yard (maybe E-Bay too) or check with some of the other Fiero
owners to see if they have one laying around. This is where you would add
the fluid and it's easier if you have a transmission funnel too. It has a
long skinny end that fits into the tube to minimize spilling (some even have
flex hoses to make it more convenient)

If this sounds too difficult I recommend getting the transmission flushed at
a transmission shop (not a quick lube!!) It will get you the same results
for about $80-130 depending on where you live

Hope that helps