I have 2 rays. I have a california ray and a yellow spotted ray. I believe the smallest you can get is the cortez ray, similar to the california ray except found in warmer waters.The 180 gallon will be fine to house this ray for its lif span.MOst people will tell you 300+ but from my experience a 125 long is plent of space for these little guys. Most important is that you leave the tank open with just sand, if you have rock keep it small and in the corners. Good Luck! You will really love having one there great!