[somewhatshocked]

Because I didn’t cull any, my blues, yellows, oranges and reds now have a fair amount of brown decedents

Decedents or descendants? Not being a jerk here, as it does matter a lot in this case.

my temps are 75-77

Remove any heater you have. Shrimp are cool water species. I turn on fans in my shrimp tanks when temperatures get near 70ish.

can a tank really be OVER planted and maybe cause the shrimp to feel squished

No. Not really for our purposes. But your tank is only moderately planted. Shrimp do best in tanks where there are plenty of plants and hiding places.

my tank that probably has 30 shrimp including small ones about a month or two old.

That's a lot of shrimp for a small tank. Their population is likely hitting a sort of stasis.

No change in parameters or feeding or temp or anything.

What are your specific parameters? Include kH and gH in degrees.

What do you dose? How much and how frequently do you change water?

What do you feed? How much? How frequently?

 

[somewhatshocked]

Hmm lol. I mean the shrimplets and the shrimplets’ shrimplets

At first it cracked me up. But then wanted to make sure just to be on the safe side.

interesting. I thought I’ve read they thrive from 70-80? The house gets around 64-65 at times.

They'll be okay in those warmer temperatures. But they'll be exposed to more pathogens that thrive in warmer temperatures - some of them we can't even easily identify, their life cycle is sped up by as much as 50%, incubation period is impacted, etc.

They'll thrive at 64-65. I consider that my temperature goal in all of my shrimp tanks. You can definitely remove your heater. Your moss should also do better in cooler temps.

alkalinity 40 ppm
Hardness 150 ppm
KH 4
gH 9

Are you measuring with a liquid test kit or strips? Because based on PPM, you have about 2.2 kH and 8.3 gH, which is fine for Neocaridina regardless. But strips are are unfortunately unreliable for hardness testing, for the most part, because they expire way too quickly. Your total alkalinity and kH should be the same reading. Close enough, however. Hardness and gH are ~the same, as it'd probably take 9 drops to notice a change.

omnivore shrimp tabs. Only about 1/4 of a tab per day and I usually skip a day or two per week.

That's likely very protein-heavy or protein-forward. I'd add the following to your feeding rotation: organic spinach, kale, zucchini, stinging nettle, that sort of thing. Feed a different food each time you feed. Even in my most heavily-populated shrimp tanks, I feed every 2-3 days (almost never daily) and only what they can finish within an hour or so, removing any leftovers. That's especially important in small tanks.

That’s what I was hoping. Just seemed odd that it slammed to a stop

Seasonal changes also come into play. Abrupt barometric pressure changes also seem to impact them. As spring approaches, you'll probably see more reproductive activity. My tanks usually experience substantial population grown in April and May.

If you don't see new shrimp by the end of spring or early summer, you may want to consider thinning the herd a bit. I usually like to add new blood to my colonies when I thin them, as well. That almost always encourages new breeding.

 

[somewhatshocked]

Ugh, that just sucks. But you're obviously getting through it and know what to do. That's light years ahead of most people who start out with shrimp.

I’m “hoping“ they died because of the nitrites and not the stress from tetras.

The ammonia and nitrite are the obvious culprit there.

One thing you can do to increase shrimp success in your tank with fish is to provide tons of cover, lots of moss and other hidey holes. Look for ornaments that have openings shrimp can get into that fish can't. That's one of the silver linings of having kids who like glow tanks and the kind of setups we typically don't enjoy on the planted side of the hobby - tons of ornaments for shrimp.

 

[somewhatshocked]

Even their own personal Shrimp Castle

One thing you might want to consider is gettin some PVC pipe and roughly cutting it down to manageable sizes like this:

To create some caves.

Rough cutting is actually what you want, as it ends up looking more like bamboo once it's painted. You can see a smooth edge in the photo above among a bunch of rough cuts. They're painted with Krylon Fusion black spray paint. Held together with zip ties. I use them with moss attached in many of my shrimp tanks.

You could do something like that and use black paint with some other glow paints to make it look "cool" in the tank. But I'm betting black would work really well without any special effort.

 

[somewhatshocked]

Two females have eggs now! Of course it’s the two very brown wild ones, and none of the bunch of fancy ones lol

If they're in the tank with other colors, you never know what might pop up. But that's great news!

Should you end up getting any that are really solidly-colored or more solidly-colored than the rest, maybe you could try selectively breeding them with similar shrimp to see if you can eventually get some that are solid. Regardless of color, I mean. Brown, red, black, whatever pops up.