I have a 10 gallon cherry red shrimp tank (approximately 3 months old). It has 18 shrimp and 2 apple snails. I feed them algae wafers and cucmber. Plants are java fern and java moss. Shortly after I transferred the plants these little white dots have been colonizing my glass. Tried water changes, gravel vacuuming, non-feeding the shrimp for 3-4 days, squishing these shell-like things to no avail! What are these creatures? They measure approx 2-3 mm-- they seem to have a clear shell and I can swear I can see movement inside. Attached are pics: