I understand that you really like the Jardini, but you already know that the 125 will not be large enough to accommodate an adult Jardini, and really, I wouldn't suggest keeping it in the 125 past maybe 12-14". With that being said, why sacrifice all of the other fish in your 125 to "make room" for a fish that won't fit in the end? You may need to consider the alternative of asking that fish store owner you are buddies with to hold on to the fish for you for a while, until you are able to provide a large enough tank to house it. (assuming that the store owner has an empty LARGE tank he can dedicate to doing that) I loved my clown loaches, and still miss them/want to get more.. but I gave them up realizing that my 55g tank just wouldn't cut it once they started to grow more. (gave them up at maybe 4" or so, got them at about 1.5") It is never an easy decision to make, but it isn't really fair to the animal to be kept in an enclosure far too small to accommodate its adult size. Please, take a moment to consider what is best for your fish, not just what you would like to do with it.