Here is what a person on ** Please do not name other forums. Thanks -Sep said about keeping rays/sharks. It sounds like 180 is fine.
First, some info on tank size. 125 gallons is a *small* tank. The minimum tank size for any of the cat or bamboo sharks is 6 feet in length, by 24 inches wide. This amounts to a 180 gallon tank. Again, this is the minimum size, not only for the sharks but for the ray as well. You should know that I'm not just quoting numbers from some book, but speaking form experience. I've kept these animals in the past for several years.
Secondly, most triggers are very poor tank mates for cat sharks, bamboo sharks, and rays. I've seen them lose eyes to curious triggers on more than one occasion in store display tanks. Appropriate trigger species would be the niger, Bluejaw or crosshatched triggers. Tangs are fine, as are angels, larger damsels, groupers and lionfish. Again, a large tank is needed for some of these fish, larger than 125 gallons. I suggest you budget for at least a 180 gallon tank.
Cheers
Jim<<<