They do. I had a 50 that I'm trying to sell and it was a freshwater and all of the tropical fish swam in circles and had little fights. My 100g with cichlids is amazing! 2 oscars, 3 convicts, a blood red parrot and a pleco. Every time I walk into my room they come up and swim really close to the glass and follow me throughout the room, and their colors get really colorful to. Cichlids are so much better!