Dolphin Pet

The Dolphin Pet is a Pet that can be obtained directly from Fishing. Unlike other Pets, the Dolphin is obtained via milestones, similar to the Rock Pet.

How to Obtain
The Dolphin Pet is obtained by killing Sea Creatures. However, the kill count starts from the time of the Pets v2 update, not the start of Skyblock (Kills from before the Pets v2 update will not be counted).

The milestones are as follows: Players can see their progress to milestones in the fishing skill menu after unlocking the first milestone.

Kat Caretaking Costs
Kat can upgrade all rarities of this pet except Legendary; this costs varying amounts of money and sometimes resources. For each level the pet has, there is a 0.3% discount. For example, at level 50 there will be a 15% discount to the price listed below. Also, the cost listed is for the pet of that type to be upgraded, after which time the rarity will be that of the above type. The time listed is also in real life days as opposed to the in-game equivalent. However, Legendary is not really worth it. You are better off sticking with the Epic variant.