Vitality is the "heart" value displayed for many creatures and plants in your reef. It totals individually in four categories for Plants, Rare Plants , Rare Fish and Guests . You can verify your current vitality on the Vitality Screen. Simply tap the heart in the upper right corner to be taken there.
The Importance of Vitality
Tap the ? on the Vitality Sceen and a (somewhat vague) explanation appears:
Reason 1: Getting New Rare Plants
The description above seems to suggest that having a high vitality can improve the chance of attracting new fish to the reef. This requires growing a Rare Plant that is not already present in the reef. While it is true that growing a new rare plant will attract a new rare fish, there is no conclusive evidence to either support or contradict whether having high vitality actually improves the odds of it happening.
Reason 2: Patches
Patches allow you to save space on your reef by letting you combine four plants on one space. This becomes increasingly important at high levels. For level gained, additional patches will become available, but only when the required vitality is reached.
How Vitality is Calculated
Vitality is a sum of four category values. Each of these values has a cap of 100%. If the vitality in a category exceeds the cap, it is not added to the total for the current level. But when the next level is reached, the threshold values are raised and prior excess vitality is then added to the total, up to the new cap for the new level.
The Four Vitality Values
This is the total of the vitality of all ornamental plants . As more mystery and enigmatic seeds are grown, those that do not grow into rare plants will become ornamental plants. And, although the FAQ on Disney's support pages indicates otherwise, multiple ornamental plants of the same kind are indeed counted in the total.
This is the total of the vitality of all rare plants. As with ornamentals, multiple rare plants of the same kind increase the total for the category. This makes it significantly easier to keep the value for this category at or near 100%, when compared to the category for rare fish.
This is the total of the vitality of all rare fish. Each new rare fish increases vitality. Getting new rare fish from rare plants becomes more difficult at higher levels. Fortunately, occasional special events include rare fish as a reward, and these also count toward vitality.
This is the total of the vitality of all guests in the reef. If each guest is retained at the time it first appears, this value will usually be close to 100%.
Optimizing Vitality & Reef Space
When higher levels are reached in the game, keeping vitality high while allowing enough space for growing plants and attracting guests and other creatures can become quite a balancing act. As time goes on, it often becomes necessary to remove some items, particularly rare and ornamental plants, in order to make room for new and better ones.
When this occurs, it is possible to either delete ornamental or rare plants, or move them to the inventory. Deleting a plant will decrease the vitality value for that category, unless the value was already above the 100% threshold. In that case, it depends whether the loss of vitality from the deleted plant reduces the category total to a value below the cap. Because the individual category values are not displayed in the game, it is best to exercise some caution during the optimizing process.
With regard to ornamentals, some good advice is to just keep smaller ornamentals with high vitality which occupy only one square. Keep in mind, though, that some of the 2x2 square ornamentals are also part of combinations, and some of both sizes may not be available in the nursery to be re-planted. In any case, it is best to remove lower value items first, and check the vitality value during the process, to avoid it dropping too far, too quickly.
As for rare plants, begin with the lowest vitality rares. The last of each kind of rare plant can not be deleted, so there is no risk of losing any rare fish associated with a rare plant. As with ornamentals, some rares may have been available for only a limited-time. Again, check the vitality screen during the process to avoid excessive reduction in values.
Vitality Values Per Level