bubble coral question

[AlienAnchovies]

well for a week now my bubble coral has been wasting away on one side, then today i noticed that theres half a skeleton and half healthy tissue
what the hell happened, all my water parameters are in order and every thing else is doinging fine, even the birdnest frag (which is in a shaded spot) i got from josh is growing all exept that **** bubble, i dont have much light on the tank (18 w pc 50/50)

[alexwolf]

how big is the tank?

[AlienAnchovies]

its a seven gallon mini bow, i feed the tank phytoplex and microvert every 3 days, am i supposed to feed the bubble directly?

[AlienAnchovies]

i just stuffed a chunk of krill in it and now the healthy side has expanded and some of the unhealthy parts did as well