3 other ways: 1st is difficult, 2nd polluting, 3rd requires slightly moving coral forward.
Pre-conditioning (let it smell the food): 15-20 min after largest fish feeding or after adding a pinch of cyclop eeze. Then try to feed by any of the following methods:
1. Placing mysis onto most mouths. Tweezers or long plastic tongs, depending on tank depth. At 24"/60cm it will be difficult, but doable.
Keep flow off for some time. Repeat.
2. Repeatedly shower coral by food. Flow off and on again, repeat showering. The whole procedure may take from 40 min to 1.5 hrs daily for 3 days, then it may start open by itself.
Battery operated gravel cleaner may help remove uneaten food, or just siphon it off.
3.
Lunar Lander, weightened version of "half bottle hut". Food is injected in closed compartment. This bell is removed after feeding.
HTH
If you don't mind unasked advice, the orange gorgonian in front of Tubastrea micratha requires more frequent feeding, IMHO

ZoPlan, RotiFeast, frozen rotifers - whatever you have.
Is is Swiftia kofoidi? Mine:
