You plan on naming all you Nids? Good luck.
lol
Maybe you should go the George Foreman route and name them all George.
Let me start with photography. Take pics of the models in front of a solid clear background. Try NOT to use a white background because that fools the camera into thinking it's sunny and it closes the aperture making the model dark. Refrain from using flash. Flashes are horrible when showing detailed work on small miniatures. Wait until mid afternoon when it's nice and bright.
Now for the model. I like your colors. My first model I ever painted was a Nid from the 4th edition Battle for Macragge starter set, and I used the exact same color scheme. I would say that you have a solid painting foundation, but you need most improvement on is clean up/touch ups.
Let's begin with the base, you should either paint the rim brown to give it uniformity or paint it black to frame the model.
I'm not crazy about the hooves color. I think they stand out too much and don't blend in with the rest of the colors. I would use black or dark grey instead.
There's no clear division on the body, it's one solid mass of red. You need to paint the joints a different color. You can either go darker or lighter to show soft flesh.
You need to take care to paint the teeth, right now you can't even see them because they blend in with the face. Also, you should change the tongue color for the same reason. You can do, pink, purple or green.
Red is a very difficult color to pull off right. You need to do several thin coats. You can see some of the black still showing underneath the red. Several thin coats is the way to go here. Same for the blue. you can see black underneath.
Do several thin coats of the blue, then do the edges in a lighter shade of blue. You'll essentially start at the edge and paint your way in, creating a 'streak' effect. You can see that on the picture below.
I like to look at pro painted pictures of models before and during painting so I can see all the small little details that I might have missed otherwise.
Like I said, you have a solid foundation, you just need to focus on the clean up. Do a search for "Tyranid dip" on Google, it might be an option for you.