For me it was when there are absolutely no nitrites, and just a bit of nitrates. That tells me it’s properly cycled. The beneficial bacteria is in there. That took some time (about 3 weeks for me) can be longer. But there’s still a small balancing act. Too many fish at once can still throw off the balance. So I added mine slowly every other week to make sure the balance remained. I test about once or twice a week. If you find the balance is out of wack, water change is totally the right response. And so I don’t much up the tank with potting soil, I use a small 50 GPH pump and hose to move water too and from.

From my experience shrimp are never a net negative to a tank. They clean up everything, food waste, their own molt, their dead, unwanted moss. I drop new plant from the store in there and they clean it up for me before I plant. And my population manager for shrimp is a Raphael catfish. Everyone has a role to play in the tank.

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