Would it be OK to put sand on top of the existing gravel, the reason being I just got 3 more tiny peppered corries to go with my existing 3, it will only be a temporary fix because as I will be getting my 60g set up soon so all fish will be transferred into that when its ready, my existing corries have had no problems on the gravel and all of their barbs are fine, but the new ones are so small and I'm a bit worried for them, especially when the majority of people say corries should be kept on sand