<https://forum.aquariumcoop.com/topic/11418-perfectly-round-white-spots-on-my-aquarium-glass/>
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"Despite a true siamese algae eater in my 20 gallon freshwater tank, I've had a recurring problem with algae on the aquarium glass.  Last Saturday, I decided to refresh my aquarium.  I moved the fish (the algae eater, 3 corycats, and 3 neon tetras) to a temporary container, washed the gravel and decorations multiple times, rinsed the Biomax and Eco-Bio block, and replaced the carbon and foam before refilling and reloading the tank.  I used a bottle of Tetra SafeStart to immediately restore a healthy bacteria environment.  On Monday, I purchased 5 new neon tetras from a local pet store chain.  I did not quarantine the fish, I just rested them in a container of water from my tank for about an hour before adding them to my tank.  Then last night (Tuesday), I suddenly noticed small groups of perfectly round white spots on my aquarium glass.  I have attached two pictures.  The white spots are circled in red.  Does anyone know what these spots are and whether my fish are at risk??  Your advice is greatly appreciated.\n \n\n\n\tBTW, all of the fish appear healthy and happy.  The new neon tetras are shoaling with the old neon tetras, the corycats are more active than ever, and the algae eater is hanging out as usual.\n \n\n\n\t \n \n \n "
<https://forum.aquariumcoop.com/topic/11418-perfectly-round-white-spots-on-my-aquarium-glass/#comment-89364>