Bob, Sailfin mollies and black mollies are different. Black mollies don’t get as big as sailfins. Sailfins come in an assortment of colors ranging from yellow, orange, red, black, white and calico. However, they’re most often available in their orange form, usually running around $8-$12/pr.. Bob, how much salt do you put in your tank? Most fish can tolerate an unusual amount of salt in their water and it sounds like a few scavengers could help you out in eating leftover food. My dbts used to have a hard time catching guppies when they were smaller (2″). They were constantly chasing them around but never catching any. Yet, I noticed the guppy population dwindling on a daily basis. I finally figured out what was happening when I happened to observe the dbts at night after the aquarium light went off. Well, the guppies would lie down at the bottom of the tank and take a snooze and the dbts would ambush them in their sleep! They ate a lot of those guppies that way! Chun