If the haitiensis prefers sinking pellets (or if you have other smaller fish to feed) then I would recommend the 3mm large fish formula. If he prefers floating pellets like my 10" flowerhorn does then the 4.5mm jumbo fish formula would be perfect. My FH makes a mess chewing the 6mm thera+A formula I feed to my 16-20" fish but he swallows the 3-4.5mm pellets whole