It should be cool as long as you are prepared to move it as it grows. I use my Naso tang as an excuse to get the 125 with the misses. Even she knows it's too cool of a fish to get rid of (it actually likes to be petted, and insists on jumping in front of the camera when your trying to take a pic of anything else). Bear in mind though that a lot of hippo's arent much fun to watch. I had one, and as soon as anybody got close to the tank it scooted away into it's hidey-hole. The only time I really got to view it was during feeding. Seems a lot of other's report this too.