What do you use to create your blackwater?
I think as long as you don't use too much Indian Almond leaf, it should be fine.
Too much usage of Indian Almond leaf is also unhealthy for the Betta.
Make sure that your pH is not too low like below 6.5 and GH 5-8, most Cherry red shrimps will be fine.
General Hardness (GH or Total Hardness) is an important water parameter to shrimp keeping and breeding. Unfortunately, Carbonate Hardness (KH) and General Hardness (GH) are commonly confused. General Hardness (GH) represents the overall concentration of salts (calcium, magnesium, iron, etc.) but...
aquariumbreeder.com
Neocaridina shrimp water parameters, like pH, should be correct as well as constant. Water parameres like pH and TDS for other species like red cherry shrimp should be stable as well.
theaquariumadviser.com
Some information for you.
Summary of Blackwater Fish Needs The term "blackwater" refers to soft, acidic water which is deep brown in color, like clear tea. The dark brown color is due to organic acids in the water. Many river systems of northern South America including the Rio Negro and the Orinoco have blackwater. Some...
aquariumscience.org