The most common redtail barracuda is A. falcatus . They need as big a tank as possible, they school pretty well. The need fairly well-oxygenated water. 99% of the time , they will not eat anything but live food. In aquaria , I personally believe that a true 10" barracuda is is about as large as i've seen. P.S frequently making large partial water changes is advised, as they seem to thrive more this way instead of just surviving!!!!!!!!!!!