In Minecraft, axolotls only eat buckets filled with tropical fish. To feed them, you need to use a water bucket on a tropical fish to get a bucket of tropical fish. Once you have the bucket of tropical fish, head over to your axolotls and use it on them. The tropical fish will disappear, and youll see a bundle of red hearts appear above the axolotls head. Feeding axolotls tropical fish buckets can allow them to breed as well as speed up the growth time of babies. Each use of a tropical fish bucket on a baby axolotl will speed its growth rate by.