Pics did not show up. 7 Discus is better provided you have a large enough tank to house them. Feeding is probably best done with a good mix. Much easier to feed. FBW's are a nice treat or snack. You are correct in putting a sponge pre-filter over your filter intake. The couple HOB's I have I never shut off...but have pre-filters. I use sponges and plain paper towels to do my wipe downs. Whatever you use, make sure it's fish safe...no soaps or chems added, especially when looking at sponges/scrubbies...Bill