I have a 3.5 gallon tank, about 70 degrees F, with moss balls instead of a filter, it is used exclusively as my nursery for my baby fish. It has been up for months now, and I have used it to successfully raise zebra danio fry, until they were big enough to join their parents. Then one of my ghost shrimp mothers had eggs, so I put her in the nursery until the baby shrimp hatched, then returned her to her tank. All was well, the 35 or so shrimp, were doing well. But the tank had allot of algae growth. So I got some small pond snails for it. They cleaned up the algae and laid a bunch of eggs of their own (around 100). They and the shrimp seemed to be fine. Then the snail eggs hatched, and 2 days later all the ghost shrimp were dead!!! (rather disappointing, my other batches of ghost shimp have made it (I used them as feeder fish)) The baby snails are still fine, but all the shrimp fry are dead, they were about 3-4 mm long and about 2 months old. Could the hatching of the 100 or so pond snails have caused the sudden death of all the shrimp?