OMG You can get leeches in a FW tank? Are you kidding me? Something else to worry about. I think I'm going to start soaking new plants in a mild bleach solution after hearing that one.
thread like? detritus worms maybe? the arrowhead are planaria...Whether or not planaria is harmful to shrimp is debated, some believe they "sting" the shrimp and can cause issues when they are in great numbers. I have seem them effect the health of snails. This is why I "preach" gravel vacs even in shrimp tanks since there is no predation for pesties.
OMG You can get leeches in a FW tank? Are you kidding me? Something else to worry about. I think I'm going to start soaking new plants in a mild bleach solution after hearing that one.