Also, before I spotted him, I had just finished with removing a stake that was supporting my fiddle leaf fig plant in the container.

It llooks like a fungus gnat larva.

Thank you. When I spotted this larva, I thought this could not be a fungus gnat because an adult was about 4-5 times smaller in size.

About 3 weeks ago, I noticed one tiny fly in the top soil of a different plant while watering. I had watered all my houseplants that day, and been bitten by what I thought were biting gnats/fungus gnats. I tried the apple cider vinegar trap which didn't catch anything and also completely dried at least 3" of topsoil (didn't water any plants for 10 days). However, all the gnats disappeared in 2 nights. I shelved it as another unsolved mystery. I read about the lifecycle and transfer to other houseplants. I am puzzled! Is there any chance it could be anything else?

It might be a fungus gnat larva but it might not be a fungus gnat larva. I have read that fungus gnat larvae might be bad news in large concentrations because I have read that they can damage to roots. I have never had a large concentration of larvae so I cannot attest to that but do know that a few gnats do not cause any problem. Please be aware that the presence of fungus gnats is an indicator of possible over watering.

Looks like a fungus gnat larva. They feed on algae, fungus and decaying plant matter. They are not harmful the plant, but are extremely annoying to the gardener! Most peat based commercial soil has fungus larva or eggs in it, and yes, fungus gnats are an indicator that your soil is too water retentive.

I use Diatomaceous earth powder scratched into the top of the soil, along with a soil that does not retain as much water, such as 5-1-1. A good ARTICLE.

Fungus gnat larvae are absolutely a problem for containerized plants, as they are very likely to feed on the tender root tips of house plants and will contribute to the decline of houseplants if allowed to multiply freely.

However, based on the one image, I couldn't swear that he's a FG larvae at all.

How much of a hazard fg larvae present depends on how high their numbers are. They feed preferentially on fungi (hence the name) and decaying organic matter. However, if populations are very high, they will turn to tender root growth. Seedlings are at greatest risk.

Also not sure that is a fg larvae.

If it is fg larvae, then there a number of management options. One is to change your media to a less organic one (particularly one that is not peat based or contains compost which has not yet fully broken down), or use water infused with Bacillus thuringiensis var. israelensis which is found in mosquito dunks (sold in many BBSs, looks like a grainy donut, and is used often by folks with small ponds near their home). Personally, I don't worry about them. I have a lot of carnivorous plants. They keep the population in control for me.

I’ve had swarms of fungus gnat larvae in my mix before and they usually always have a black dot at the tip of one end like this:

Thank you for making the time to illustrate the size and features of fungus gnat larva.

It has been about 3 weeks since my post (cycle is about 2-3 wks based on what I read) and I am hoping that I don't have fungus gnats atleast a huge infestation since I haven't found any flies in the soil or around containers, nor have I been bitten again.

For what its worth, about a week ago, I found another worm..this one was even longer. It was pale brown (not quite straw colored like in the pic) and could not tell whether it had legs. When I gently poked its center, it coiled up on both sides.. kind of like how an earthworm does. But before I could decide whether or not to place it back into the container, my husky puppy had scooped it up!

Thank you all for your inputs :)

Now that’s a nasty puppy lol! The fungus gnat larvae are usually pretty clear and shiny/glistening skin. It had a very wet look to its skin and pretty transparent looking so those worms you’re finding def shouldnt be fungus gnats. They don’t tend to bite me either so I’m not sure what you have. Maybe a mosquito larvae? They wouldn’t always hang around your plants indoors and they do bite us lol