Hi I see you live in California. Where exactly? Is the plant indoors or outdoors. I can't tell from the photo which cultivar you are growing. It looks like 'Encore'??

If it is outside and you live away from the coast then it may have gotten sunburned. Move it into bright shade. Indoors they usually don't get burned unless right up against the glass on a sunny window. What to do?--probably move the plant and trim off the burned tips. My plants will get what I call "heat burn"--the foliage gets marks over the old and new growth, that turn brown and dead. It is a pain, and it takes a year or more to grow out of it. I find that frequent watering in summer and keeping the plant out of too much light helps to prevent it. So far this year I have done well, but now we are getting into our hottest months, and the heatburn usually happens in the latter half of summer. Its been hot these past few days and I am about to go out and see if the plants are suffering. I will be watering them anyway.

Jon

hi,
where i live it is HOT all summer (prob similar to you) but now we are after an exceptionally hot 2 week heat wave and my goldfish plant also got sunburned. what i do is this: the leaves that just get the round patches i leave but leaves whch have gone all brown i pinch off. you can move it into slightly less sunlight but if it is in a shady spot it will not flower. at least this is what happened to me and how i found the perfect spot for mine: a few hours sunlight, a few hours filtered sunlight and the rest of the day it has light (not under patio roof but basically shade.
so, pinch off, move to slightly less direct sunlight while it is recuperrating but DON"T overwater!!!!

btw, if necesary these plants can be cut back as much as necessary.

good luck,
dory