According to series animator Vincent Waller, “there is absolutely no meat in the Krabby Patty. There’s no animal product in there”, something which was always planned by series creator Stephen Hillenburg.[9]
…
he stated that there is no meat served in Bikini Bottom except at the Chum Bucket.
AFAIK SpongeBob is not vegetarian.
Definitely not, according to the Bikini Bottom Horror.
https://en.wikipedia.org/wiki/Krabby_Patty
https://makeagif.com/gif/spongebob-clip-14-eating-montage-club-spongebob-ep-X8cHaN