Clown loaches can get massive, but it takes a lot of years for them to outgrow a 125. The females typically get the largest, I have seen CL's that are 15 yrs old and only 7 inches, most likely males. Jumbo sized CL's sell very easily, and for pretty good coin, if you need to remove any down the road. A group of 4-5 CL's would work well with your other fish, and personally I find them very hardy, once they have been acclimatized after import. (the vast majority are wild caught) Or, you could go with a group of Yo Yo's, they will be good for the life of your tank. Good luck.