I have 5 snails in a 10 gallon aquarium. I have a golf ball sized blue mystery snail, baby nerite snail, and 3 tiny brown pond snails. There were little clumps of yellow dots on the front wall of the tank, and now some clumps of yellow dots are on one of my tiny brown pond snail's shell. The clumps are no longer on the wall... They have been eating green algae, algae pellets, and celery. They LOVE celery.