They are lovely! Im getting a pair of super red plakats in the next couple of weeks, coming in from Thailand, I love the reds! Bettas do, ideally, need heaters. They are tropical fish and 75 degrees just isn't warm enough, especially since the temperature of the water is always a degree or 2 lower then the temperature of the air. Low temperatures can cause bettas to act lethargic and can compromise their immune system leaving them more susceptible to disease. Also higher temperatures promote spawning behavior so conditioning breeding pair in water thats between 80-82 degrees F is ideal