Unfortunately, I think all of your fish are doomed. You have way too many fish for an uncycled tank and they already have ich. By the 4th or 5th day your ammonia will be off the chart high. I didn't see any test readings so have you tested your water at all for ammonia, nitrite, nitrate and pH? If not that should be done immediately. Start water changes as often as possible to keep the ammonia and nitrite as low as possible and remove the arbon from you filter before you start treating the ich.
Please measure your tank and post the meausrements here so we can figure out the size (or simply multiply W x D x H x 7.48). The plecos can both grow over 2' long (depending on the type pleco) and the sharks can grow to over 3' will eventually eat anything smaller than them. They need at least a 200 gallon tank just to themslves and are not a community fish. Here is a good profile on them.
As already suggested, try to cure the ich and return the fish. I would actually talk to the shop you bought them at about the terrible advice they gave you. They should take them back anyway.
Please measure your tank and post the meausrements here so we can figure out the size (or simply multiply W x D x H x 7.48). The plecos can both grow over 2' long (depending on the type pleco) and the sharks can grow to over 3' will eventually eat anything smaller than them. They need at least a 200 gallon tank just to themslves and are not a community fish. Here is a good profile on them.
As already suggested, try to cure the ich and return the fish. I would actually talk to the shop you bought them at about the terrible advice they gave you. They should take them back anyway.