Hi. Most fish will devour small shrimps but you just need to swing the odds in favour of the shrimp and make it harder for the fish to pick off the baby shrimp. A huge mass of moss, such as Java Moss, is the best refuge for the baby shrimp. My RCS breed very well with over 50 tetras but I have two huge clumps of moss (about a foot across in a 4 foot tank) and the babies stay well out of reach until big enough for the fish to ignore them. I do get losses but once a large enough colony is established the fish/shrimp ratio settles down. If the fish didn't control the shrimp population then I would be over-run with them.
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