Acan Question.

[smareo]

Is it normal to see an acan spewing out yellow balls during the night? I turn off my moon lights during the night for 3 hours then took a peek on the corals to see how the tank was doing. The tentacles on the acan started to retract and form a pimple like pyramid, then it shot yellow balls from each head about 0.5 cm . These balls kinda look like pus, but I asked the LFS guy he said it could be vomiting its food or spawning. I was wondering if this is normal? thanks =)