Actualy, golds shouldn't realy be combined with any other gourami species if you are after a peaceful tank. Stick with females only and go for three-spot color morphs only instead (1 per 10 gallons is a good guideline to follow). The available three-spot color morphs are golds (obviously), blue, cosby, opaline, lavender and platinum. These all grow to 6". Males have a longer and more pointed dorsal fin than females which have a shorter, rounded one and males are far more aggressive. Don't attempt to crowd them - they will kill each other and tankmates readily. Don't try keeping two males together - they'll tend to fight to the death. Also, avoid pairs of any sex - the dominant fish may bully the subordinate to death. Stick with 3 or more and, as I said before, its best to stick with females OR keep one alone.