asking Rainbow Red Tailed Shark

[astm]

hi guys
i want to ask about rainbow red tailed shark fish
i have small aquarium 50 liter
in it

1 fish fiter

and 3 fantail

and 2 rainbow red tailed shark

so the red tail always in the bottom and when i put the food
the fiter and fantail eat it and finish it
so what about the red tail ?
my fish food is small balls red and green not dive to the bottom

 

[astm]

I'm still asking
lool

 

[JakeVS]

from my little experience, that fish tends to stay near the bottom almost all of the time, and appears to be a scavenger fish. try a sinking pellet?