Fertilizing Eucalyptus, Guava

My wife and I recently ordered and received (fantastic packaging, by the way) a couple of eucalyptus plants – a silver dollar and a regular eucalyptus plant.
I've been trying to find out what kind of fertilizer would be best for these plants to help them grow (they seem to be doing very well on just regular water, but I'm sure they'd appreciate more).
Also, what kind of fertilizer is best for guava plants?

It is amazing how many nutrients are released by the potting soil! However after about a year of only watering with water you will find that the plants start to grow slower and slower and seem to be losing almost as many leaves as they are growing new ones. This tells you that the soil is getting critically depleted and can no longer support vigerous growth from the plant.
If you are growing the plant to use for food or medicine, I suggest that you use an organic fertilizer such as fish fertilizer. For the eucalyptus, a balanced fertilizer would be appropriate such as 20-20-20. Since the plant dislikes root disturbance shift it to a larger pot when the roots come out of the bottom of the pot, add a bit of fresh rich soil on top, on the sides and bottom, but try not to disturb the root ball too much.
The guava should be encouraged to flower and fruit and should therefore get a high phosphate fertilizer (the middle number would be highest). Repot into a lager pot with fresh soil when roots come out of the bottom of the pot.