New to hobby, Citron Goby + other livestock advice

[needlehandssoftfingers]

Hi everyone. Loving the hobby so far, ive cycled my 20G high with plenty of rock and started adding livestock. Currently i have a small ocellaris clownfish, emerald crab, 2 nassarius snails, a yellow watchman goby, and a few days ago i added a citron clown goby. Id like to describe how my tank is going currently as getting everyone to eat is now my current phase it feels, and everyone but the snails has been tricky so far. Also worried i overfeed trying to broadcast food into everyones mouths/caves. Had about 75ppm nitrates yesterday so i did a 50% water change and im thinking another 30/40% today? I dont know at what point i need to replace bacteria (I have Seed brand).
So far everyone is getting along great. No one is going directly at food until i stop feeding but theyll go for small bits here and there which are out of reach or if it floats right into their mouths. Hoping this is a good sign that theyll eventually trust the food sources. I have garlic liquid additive, flake, pellets, and mysis shrimp so far. the WYG started coming out of his caves today, either floating around the current at the top or checking out the glass now. i checked ammonia yesterday with a Salifert kit everything is fine it seems. Worried me at first. He breathes heavy some times, assuming its stress?
I read that Citron gobies like meaty things like mysis shrimp etc, but it looks like he gulped a piece yesterday and spit it out? Is it likely he just took a bite out or do you think he doesnt like it? Have read they/livestock can be picky based on personality? I really love these gobies but read that they have a hard time in captivity and only live 2-3 years, any info on this? He is my favorite fish ive seen so far so id really like to get good at caring for these fellas. So far hes just moving around to different places couple time a day. Ontop of one of the powerheads or in a corner where flow pushes food, or tucked in by a rock on the sandbed.
Emerald crab seems happy, only algae ive had so far was from diffuse sunlight while cycling and he doesnt seem to like this kind, or just prefers all the leftover bits im overfeeding. Doesnt bother anyone other than push a snail over when its trying to take his food haha.
My LFS was saying that I could probably handle a pistol shrimp and one more fish in my tank. We were thinking to wait and see what necessity comes up for my habitat before getting the last fish, for example wrass or filefish. Any thoughts or advice on this?
So basically im just looking for any advice or suggestions. I keep my salinity at around 1.024/5 and temp about 25 celsius, am going to be testing everything including calc mag and alk today. Just trying to figure out how much of a water change to do today. If it matters, I do have a RO/DI buddy.

 

[Sonatine]

Getting new fish to eat can be stressful. How big are the food particles you're offering? Sometimes fish spit out things that are too big to swallow. My clown did that a lot at first, and still does sometimes (it's pretty small and has a slightly deformed jaw).

Making sure some food floats by their hiding spots is another good strategy. I always had to step away from the tank at first to get them to start eating, until my fish grew less timid. It's a good sign that they're at least trying to eat, and hopefully they'll start keeping more down when they get more confident. My blenny was super shy and not eating when I first introduced him, and now, just a few weeks later, he eats everything, voraciously. I was advised not to worry too much about the fish not eating much for the first few days to a week.

 

[needlehandssoftfingers]

Getting new fish to eat can be stressful. How big are the food particles you're offering? Sometimes fish spit out things that are too big to swallow. My clown did that a lot at first, and still does sometimes (it's pretty small and has a slightly deformed jaw).

Making sure some food floats by their hiding spots is another good strategy. I always had to step away from the tank at first to get them to start eating, until my fish grew less timid. It's a good sign that they're at least trying to eat, and hopefully they'll start keeping more down when they get more confident. My blenny was super shy and not eating when I first introduced him, and now, just a few weeks later, he eats everything, voraciously. I was advised not to worry too much about the fish not eating much for the first few days to a week.

ive been crushing the flakes but i do need to cut the mysis up it seems.
I'll consider all that, thanks for the response