It was a bad batch from ninja, if you talk to them about it, they normally fix it or hook you up with a new tank
i just e-mailed ninja about cracked gelcoats. like klub said, it's a manufacturing defect and ninja has a warrenty page that you can fill in to get the tank resprayed. the cracks are cosmetic only, and do not affect the structural integrety of the tank at all. some tanks from empire (they use the same tanks as ninja) were also affected and they will get it fixed as well.