No problem, I happen to be up, so I often catch late night (where most of us are) posts. Ok, 6 guppys, 1 betta and the mystery fish. Keep an eye on the betta, they will sometimes attack other fish with long, flowing fins, perceiving them as other bettas. The guppies might or might not fall into that category, just depending on your particular betta. So, watch out for fin nipping, flaring etc., and if you see any, you might need to remove the betta. The guppies are also the rabbits of the fish world, and will breed like crazy if you have males and females. So, read up on cycling and keep an eye out for those couple things, and we can help you as you go. If the sucker fish is a pleco, which is the most common kind, he'll probably get too big for your tank. If it's an oto, that's a better size, but they need to be in schools. So, I would start by either asking the store what kind it is, and/or looking up pictures of pl*costomus (it's considered bad luck to write or say the whole name, for some reason), otocinclus, maybe chinese or siamese algae eaters, and possibly corys, which aren't sucker fish but are bottom feeders. It's probably a pleco, which means it will probably get too big for your tank, but let's make sure first.