I attached some pictures of my Chinese wisteria bonsai. It is about 4 or 5 months old and as you can see from the images it looks a little sad. I've had a problem with gnats so I've been using Fungicide 3 about every 7 days to try to get rid of them. I had been watering it about once every two to three days although over the past week I've only watered it once to try to dry out the soil and kill any gnat eggs that might be there.

Two shoots have already fallen off after turning yellow and dying. At first, they felt soft and limp, so I was sure I overwatered, but right now they feel kind of dry. There is only one new shoot that seems to be doing okayish. I just gave it a decent amount of water, after I sprayed it with fungicide. More little white gnats started to come out of the bottom of the pot, so I sprayed down there too just to be safe. The soil on the top was quite dry although I have a feeling the soil about 6 inches down was still moist.

I know it's hard to tell just from the images, but the tips on most leaves old and new have been turning brown. As you can see the pot is probably too big for the plant right now. So my question is, should I water it more, less or try fertilizing it? Should I try filling the plastic pot holder with water so gnats can't lay eggs on the topsoil? I have low nitrogen fertilizer at home (this plant is in my dorm room) so I could grab it this weekend and bring it back. Before I left for winter break and took the plant with me, it was doing very well. It was growing quickly although there were still a couple of leaves with brown tips. My window is facing to the Southeast and it gets a good amount of sun all day. I have a couple of bamboo sticks in the soil and one outside of the pot to help support the tree. I do not know if this is detrimental or not.

Sorry for the long post but I'm trying to give as much info as possible. How can I make sure this bonsai doesn't get any worse? It has a good amount of sentimental value to me so seeing it die would be kind of heartbreaking. If there seems to be anything wrong with my routine please let me know. Thanks for any info you're able to give, this is my first bonsai.

Well, first of all, this is not a bonsai but a young sapling.
Second: the only problem is that it’s inside. There is no such thing as an indoor tree.
I do not know where you live but if temps are well above freezing place it outside and keep it there. If it’s still freezing, place it in the coldest brightest room you have untill you can place it outside. Do not fertilise

Stop using poisons when there is no need. Gnats are a sign of too wet. The plants should be ouyside.

I'm not sure what you mean? Do you mean this looks like a Wisteria tree and that it isn't even a bonsai?! I grew it from a seed and the seed was labeled as a Chinese Wisteria Bonsai, which I've read are okay to grow in pots

There's a long way to young plant to be called Bonsai, there is no "Bonsai seed" you know, the seeds are normal ones, if you plant on the ground they'll grow to it's usual size... To achieve a Bonsai, people use many techniques, so it can look like an old tree, but small, all the styles (when not exagerated) mimics the trees on their own enviroments...

For example, wiring the branches, and add some curves to them, because big trees don't usually grow branches straight, as young trees do, pull them down to simulate the weight of the branches, etc...
So you don't buy a bonsai seed and in a few years you have a bonsai without using any technique.
I hope we didn't bummed you with this info, while you learn how to keep this plant alive, you should begin to research about the species, watch some videos, learn some techniques, and in a few years you can start modeling your tree to be a bonsai... That's why it could be better for some people when starting to buy a pre-bonsai, a tree that already got few years of progress, because training a bonsai takes time and learning...

And btw, yes, it looks like a Wisteria, which is ok to grow in a pot (like any tree) and they can become really nice Bonsai... Almost any of the trees you see on the streets can make good Bonsai, so you can collect their seeds, or seedlings that would be removed anyways from sidewalks, or trimmed with the grass, etc.

Thanks for the info! I really didn't know that there was no difference between bonsai and normal trees. I apologize for my ignorance. I'm not bummed out, I expected it to take about 10 years to flower anyway so I knew it would be a good amount of work. One question that I didn't ask that I can't seem to find online is, is it possible to use too much fungicide? Meaning, will it damage the plant? Since I applied it a couple more leaves have turned yellowish. However since another user said gnats are a sign of overwatering, and I gave the plant more water after seeing gnats around the bottom of the pot, I could have possibly overwatered it even more. The soil in the first 4 inches was extremely dry and the leaves felt dry too, which is why I gave it some water today.

Well, yes over-applying can damage the plants and possibly kill them. So I would advise to stop it while still time (doesn't seem that bad), and you should only fertilize trees when they are healthy.
Your problem seems to be not finding a tune for watering, and the plant being inside, and well, plants don't usually grow much on winter...
So that can be where you found trouble, Wisterias needs a generous amount of water when on growing season, but on winter, just enough to keep the roots moist, not soaked... So try to water it according to the soil conditions, and not on a schedule.
The brown tips can mean many things, including under and overwatering...

And the bamboos, that's not a problem at all, I usually put a "tutor" stick when the tree is recently planted, or young, so excessive wind won't bother the roots growth, when the plant doesn't have enough roots yet it can wobble with the wind, and that's no good. About the pot size, it's ok, and if it grows, you'll need a bigger one in a few months or a year, deppending on how the roots grow...

I understand the emotion you developed with it... We all have lost trees, and it's not a good experience, but we also learn with that.
But a Master once told me, "When there is attachment, there is no reality", what he meant is that we all gonna lose some trees on the process of learning, we have to take the best from it.

Btw... Give it a read: www.bonsaiempire.com/tree-species/wisteria

Your advice has been very helpful! I'll only water the plant when it is dry over half-way down in the pot, and I'll try to limit my use of fungicide and see if the plant makes a recovery. Thanks so much for your responses (:

Most ( all) problems you have with your sapling are from being inside. Plants need sunlight, air, rain, wind, temperature changes so they can go dormant.This young plant should have been leafless now, like all deciduous trees at the moment, with new buds ready to open in spring .If they are derived from these things they weaken, which invites pests and diseases to invade. You giving fungicides weakens it even more
So , place it outside, where it belongs and you will see it thrive. Only give water ( which it will need a lot of in summer- mine drink 5 liters a day easily in the heat of summer) and let it grow. Nothing bonsai-ish to do for at least 5 years. Meanwhile , read up on horticulture ( the most important thing to know when you have bonsai), and some basic bonsai techniques you need to know ( these can be found on this site)
But again- outside with it, and it will be ok.