You'll get mixed opinions about feeding. IMO
the most common is 1x per day, whether at the same time or varied.
However, some feed in very small amounts several times per day which allows for a more natural (to the livestock) feeding regime such as they would see in nature.
In any case variety seems to be key, though some will say a certain flake or certain pellet, will be all you need.
Just remember not to over feed too much as you will have increased algae and nitrates.
I think the rule of thumb that I heard is to feed no more than can be completely consumed in 3-5 minutes.