Caridina multidentata catching living fish

I was shocked when I spotted one of my female Amano Shrimps catching a living fish. This fish (Tatia priguae) was indeed very weak, but still living.
I was very surprised to see how aggresivly this Amano caught this fish.

Amano Shrimps and Easy Carbo (same as Excel)

Photo 1; I have never seen Caridina multidentata being so red before
I was dosing Easy Carbo (same as Excel) for a long time (stopped a few month ago), and my plants did indeed grow very nice thanks to it. But my Amano shrimps (10 of them) didn't do so well at all. They simply disappeared, and were gone for approx 4-5 month. I thought they were dead.
Suddenly one day, I have discovered 2 shrimps hanging on one spot not eating. I was surprised to see them alive. Since I already observed how shrimps react to Easy Carbo in my other aquarium, I stopped dosing it and started doing often large water changes. It took a few month before I started seeing shrimps, eating around the tank, and behaving normal. And just a few weeks ago I saw 8 shrimps (4 males and 4 females) foraging around the aquarium in search for food. I was very happy to see them alive. I am still dosing Tropica Aqua Care with NPK and traces, no harm reported, but did stopped dosing Easy Carbo in aquariums containing shrimps. Instead I am dosing pressurized CO2 via ceramic diffuser.