From BIONICLEsector01

"Lightfish are" or "Lightfishes are?" — SurelNuva (Talk) 19:10, 23 March 2017 (CET)

Either one is technically valid, but from my experience, BS01 tends to use "fish" as the plural form - so I'd say "lightfish are." --Angel Bob (talk) 22:44, 23 March 2017 (CET)
"Fishes" refers to different fish species. So, Lightfish and Ruki would be two types of fishes, but any number of just Ruki or just Lightfish are fish. Master Inika (Talk) 23:04, 23 March 2017 (CET)