Using Axolotl bucket on another axolotl spawns a baby axolotl and not the one that was in the bucket

Was emptying my axolotl buckets into my axolotl pond at my base after discovering some while mining. When I accidentally clicked the use button for one of the buckets on a yellow axolotl already in the pond, a baby yellow axolotl appeared instead of the adult pink axolotl I had originally captured with the bucket.