This is more of a comment for those who have a betta in a small tank! My betta is scared of a filter. He is in a 1 1/2 gallon tank. Water was getting too gross too often. Just found at petsmart a great little filter/aerator that is quiet. Dont know how good the filter quality is yet, but it is a great aerator. Keeps the water moving with little force. There is a choice of attachments too. I highly recommend the Mini Internal Filter by Tom aquarium products. It was only $15 for a 1 to 4 gallon tank size. It may be great in larger fish tanks as an added aerator. ++++!!!