1. A 55 gallon is a great start for a pup.
2. My male hystrix has grown from 3.5" to 7" in a 3 years. He would still be fine in a 55 gallon currently. My female hystrix are around 10". They are same age and would be fine in a 125. Eventually a 24" wide tank would be better though.
Rays are easier to care for than MOST fish. However you must choose the species and sex carefully As they have different growth rates... Etc.
2. My male hystrix has grown from 3.5" to 7" in a 3 years. He would still be fine in a 55 gallon currently. My female hystrix are around 10". They are same age and would be fine in a 125. Eventually a 24" wide tank would be better though.
Rays are easier to care for than MOST fish. However you must choose the species and sex carefully As they have different growth rates... Etc.