Looking for midcolumn fish suggestions.

[seahorsedreams]

Hi, I'm new here and am looking for suggestions for a "swimming" larger fish for a 90 gallon Scorpion tank. He can't be a picking/grazing fish, large enough to not be eaten, not a jumper (this will not have a top) nor can they be intolerant of nitrates of about 20.

Inhabitants of the tank will be

1 Dwarf fuzzy lionfish.
Cockatoo waspfish
2 Ambons
3 Leaf scorps
1 S. littoralis