I have (3) flowerhorns in a growout, got them under 1 inch and are now about 2 inches. What other types of fish would go good with these? Im looking to get a few more smaller fish, grow them out, then transfer to main tank.
I wouldn't put other Cichlids in with them. Tankmates as far as Silver Dollars, Clown Loaches (if there's enough room) some sort of plec or catfish....those should be fine. People too often want confuse 'tankmates' with 'other Cichlids' and it often doesn't turn out well. What's already in the 'main tank' and what size is it? FH's get big.
I have 3 FHs in with a Jag, Oscar, Midas and several others and so far no problems. Although FHs can go postal for no reason at all. Yours are still small. Try a fish that can match their temperment. You could try an oscar or even a midas. Just keep a close eye on em cause you never know what will happen. Also a lot will depend on the size of your tank. The larger the tank the more tolerant the fish will be to one another.