Introducing and Seeking Advice

Hello everyone! New member here, both to the site and to owning a water pet. Only ever had dogs and recently I decided to purchase an axolotl. I had been planning on getting fish and purchased a tank and some of the basic necessities. I did all the research and made sure to write things down and ask a lot
of questions. Currently the axolotl is in a 10gallon tank. He/she is only about 4 inches and looks pretty tiny. Looks very healthy as of the past 3 days I have had it but of course I am no expert and have really no idea how to identify any health issues. I have done some reading but I am pretty nervous because I know they are very fragile and he/she is so small. I am constantly googling and double checking so i’m very thankful I found this site. I do have a 20gallon long tank which i am going to switch it to with sand once it gets a little bigger. there is no sand in the 10 gallon tank as of right now because thats how it was set up when I got it and again it is very small and would not pass all the sand. I do have hides, a thermometer which is currently at 65° (i have a water cooler coming today), i know about water conditioning. i have had he/she for 3 days and changed about 20% of the water because there was some left over food i missed when cleaning. I feed it 2 times a day only a few small worms but I am a little worried because I have read about overfeeding but its also pretty small so I also read thats how much you should feed the small ones. im not really sure honestly. Also he/she has not pooped since I have gotten it. Ive been feeding black worms which is what the person i got it from was feeding. I have a filter with a sponge overtop the water intake so it doesnt harm the axolotl. I also use Fluval Cycle Concentrated Biological Booster to kill ammonia and nitrites. no direct light over the tank or anything like that. I basically replicated the habitat it was previously in and purchased all the same things the person was using to take care of them.
As far as behavior, thats something im really interested in knowing. He/she will roam the bottom of the tank and watching it eat is so cute. really good at finding food even if i drop some and it floats away. Its gills (i think thats what the fluffy things on their heads are) look very vibrant and its like they wave at me everytime I approach the tank. I will attach some photos below but feel free to inform me if I am doing something wrong or if there is anything I am forgetting. Or if I am doing fine I could use the peace of mind as well. Thank you!

Hello,
You said you've had your axolotl for 3 days.
Have you previously cycled your filter for 4 to 6 weeks ?
If no, your axolotl will be exposed to a nitrite spike.

a couple of things you do need is a air-pump and air-stone, a freshwater test kit (saltwater test kits don't include low ph and the colour chart for nitrate is higher ie.. 10ppm for freshwater is 20ppm for saltwater), the test should be a liquid test for accuracy.
a lid, axolotls have been known to jump out.
Ideally the tank should have been cycled before putting your axie in.
a cave or hide are good because they tend to rest during the day and like dark places to do so.
in a established tank water changes only need to be done about once a week at most, this is mainly done to remove nitrates.
15°c - 18°c/59°f - 65°f is classed as ideal temperature, 4°c - 24°c/39°f - 75°f is classed as the tolerant range, anything above 20°c/68°f risks stress, below 10°c/50°f will cause them to be very sluggish and will cause a lack of appetite. the main thing is to keep the temperature low and steady with no fluctuations.
it isn't so much as conditioning the water as in making sure it is dechlorinated and also moderate to hard water. look up using holfreters solution. do not use any dechlorinater with slime coat protector as some can be harmful to axolotls (aloe vera is a big no no).
the bacteria booster doesn't kill ammonia/nitrites, the bacteria consume/convert the ammonia to nitrites and then nitrites to nitrates, which is why it is important to cycle the tank to make sure there is bacteria to perform this action and that there is enough bacteria to cope with the amount of waste produced.
axolotls have poor eyesight and don't like a lot of light, they do however have a very good sense of smell and it has been found that they can detect the electrical charge of live prey.
it's good that you have covered the inlet pipe with a sponge as there has been a few cases of axolotls being trapped/injured by the pump inlets.