Tabitha
Yes...nocturnal means they more rest in the day and are more active in the evening/night
noselessman
Most catfish are nocternal. They are less active during the day, you wont see them as much durin the day, especially if you have blenty of hiding spaces like you should. They should be fed in the evening, not during the day. Although they feed a lot on the algae growth, they should be offered things like spiraluna wafers, algae discs...
Aron
yes. a majority of catfish/sucker fish are nocturnal.