Harold William "Bill" Reginald is a blue fish who usually wears a white shirt and a red Speedo. Like other character models, his appearance is not perfectly consistent, and in some episodes he is completely naked. This means that the two names the basic design was referred to as could indeed be separate people. He appears to be ill-tempered and cynical in most of his appearances. His name was revealed in the episode Roller Cowards. In Porous Pockets, Bert calls him "Bill". However, his name was confirmed in Gary in Love as Harold. He has been voiced by both Doug Lawrence and Dee Bradley Baker. Lawrence gives him a more common American accent while Baker gives him a English accent.
"You! come back here! You've gotta help me clean this place up!"
"You brought this on yourself Harold. I did not Harold! Yes, you did harold. Harold, I did not!"
"BIG MEATY CLAWS!!!"
"Bring it on old man, bring it on!"
"Oh no! CHUM!"
" Aw, does baby want a Krabby Patty, hmm? "
"[Covering his mouth] Ooh! Oh... [Faints]
"How dare you! You toyed with our emotions! [Pointing at Plankton. Pokes him] "
"So, you like kicking butts, do ya? Well WE'LL SHOW YOU OLD MAN!!
"One patty please."
In Season 1, he was usually shown either naked or only wearing his red shorts.
In Roller Cowards he was called Harold while in Porous Pockets, he was named Bill. This may be because his name was changed to Harold for the Fiery Fist O' Pain Commercial. Though in Gary in Love, he talks to himself, calling himself Harold. It can be presumed that his real name is Harold.