That does sounds like they are getting ready to breed, the only problem is that when the fry hatch, you prob. won't have time to remove them before your loaches, red-tailed shark, and SAE eats them. They are all pretty much in that bottom feeder family, which the fry will be at the bottom until they can start free swimming in about 3-4 days. Since they will be at the bottom, this will make a great snack for all those bottom feeders you have.
If you are getting serious into breeder these guys, you either want to take all the fish back to your LFS besides the kribs, let the kribs breed and such and then sell the fry. After you get more money you can then go and buy a bigger tank and get some of those fish back that you previously had.
The other option is just to buy a bigger tank now, but that's if you have the money. Even if you do get a bigger tank, your loaches should be kept in schools of 4 or more. Since they get soo big, they need bigger tanks to be kept in schools, and I don't know if you would be able to get something like a 120G tank for them. If you do decide to get a bigger tank and can't get a big one like I suggest, I would take those loaches back and maybe get some other loaches that stay fairly small. Say suitable for a 55 gallon.