When opening a chest with shulkers full of bucketed mob it lags

If you open a chest with shulkerboxes full of bucketed fish, ist Takes some seconds for the game to process. The more shulkerboxes, the longer it takes. This is only the case with tropical Fish and axolotls, because it Shows the information what kind it is if you Fish it out the ocean for example. The Same for axolotl with the data of color and adult of baby.