NIFREL, a new facility produced by KAIYUKAN, is not like an aquarium or a zoo but allowing visitors to intuitively experience the beauty and wonder of living creatures. Ofcourse otters are on exhibition.

Here's an another article while stayin' Guam, about UnderWater World (UWW).

I stayed Guam just three days and had a good time. Ofcourse I visited Guam Zoo which is owned by Mr. and Mrs. Cushing. Although there's no otters, it was really awesome.