Sounds bad - my bad experience involved a friend helping place outdoor lighting, covered [thought safe] using an indoor extension cord. After some rain and I plugged it in: absolutely scary noise, said to be an explosion. Never ever again. Be careful please. :)

I think you answered your own question. No. It's not ok.

have an electrician come out and install an outlet adapted for outdoor usage. you will need to have a cover for it. It's not a big deal. I have 3 outdoor ponds w/filters and pumps. all have outdoor rated outlets.

What's the concern, specifically...is it if it gets wet from rain?

I live in an apartment. Is it possible I could get away with no pump/filter if I do frequent water changes and it has plants?

Your outdoor light fixture should be outdoor rated if I understand the question. Maybe post a picture .

not a good idea. is that outlet even a gfci rated? (if it gets wet it will automatically trip the breaker)

if all you want is plants in your pond, no filter needed. get a few more aquatic plants, you can even throw in a pothos plant (I have one in a vase of water w/all the roots and it's never dirty) and it will take care of itself. the water will stay clean. every so often siphon off a bucket of water and replace w/new water (if it seems to get a little smelly or dirty). otherwise, don't worry about it. Do not put small rocks or pebbles on the bottom. they will trap bacteria and debris. if you want to use large rocks, that's fine

you could do a solar powdered air bubbler for your fish. if all you have is those two, it's fine. hopefully they aren't koi.

Frying yourself or your fishies is a bad idea to most people. Exterior outlets need to be rated for exterior, and be GFIs.

Anywhere there is water and electricity, there is the chance of electrocution. You’ve got a double risk. A halfassery electrical connection getting damp and leading to a big pool of water. Nothing could be a worse idea if you sat down and plotted a way to kill someone deliberately.

Thanks everyone. I have a couple of comets in there righr now until they outgrow it. I got a few more plants and was able to plug a pump through the window into the apartment. The pump I bought is indoor/outdoor and is three prong. I should be good now right?

NOOOOOO

no. you need to understand water and electricity. anytime you have the two together, you need a gfci outlet just in case,,,,

you have an electrical unit submerged in water. it's plugged into an electrical current in your wall. if something happens, whats to keep you from getting fried if you stick your hand in the water or it shorts out and starts a fire in your wall? nothing. get the proper outlet.

as stated, you really don't need a filter unless you plan on growing fish in there. in which case, it's too small and you need a diff set-up.

Ok..I think I'm understanding this. Will this work to plug in between my outlet and the fountain plug?

it's easier just to switch your outlet to a one w/the gfi. it's very simple to switch out, it's cheaper, and you'd know it's safe. do you have a super or someone who does work around the apt bldg? he can switch it.

I actually have that yellow one on one of my filters (I needed an extension from my gfi outlet). and they do work. saved me from getting electrocuted one day.

I've been looking at solar pond pumps. I just started researching, so perhaps it isn't feasible, but I am looking for a small one for a small waterfall.

Some run on a marine or car battery which is charged by a solar panel during the day.