With your Betta Fish, you can have 5 ghost shrimp in your 5.5 gallon tank. While some Bettas may not mind, some may be bothered by the presence of a Ghost Shrimp! They are scavengers who will eat anything they can get their hands on with their tiny pincers. They aren't algae eaters by nature, but they will consume bush algae that other algae eaters won't touch.  The best option is to start from the bottom and see whether the Ghost Shrimp disturb your Betta. If your Betta isn't eating, you can continue adding ghost shrimp, but in a 5-gallon fish tank, ten ghost shrimp is a safe bet. Every few days, it is recommended to change some of the water (only 30-50 percent ). Clean the tank at least once a week to avoid harmful waste accumulation. Ghost shrimp might very well thrive in a wide range of water conditions. The ghost shrimp may live happily as long as the temperature is between 65 and 80 degrees Fahrenheit and the pH is between 7.0 and 8.0. Bettas require a temperature of 76-80 degrees Fahrenheit (preferably 78 degrees Fahrenheit) and a pH of 7.0 or above. As you've seen, they complement each other wonderfully in this regard. Furthermore, they both enjoy rushing water (provided that the stream is not too strong). Also, ensure that the tank is cleaned and the concentrations of ammonia, nitrite, and nitrate are minimal. Your Ghost Shrimp will perish and your Betta will grow unwell if they rise too high.