I've seen it happen with my Rams. After the eggs are laid and fertilized, often times the male will be the primary caretaker of the eggs, and will defend them aggressively.
The problem might be that the tank is too small.
I've also seen the female eat the eggs. When this happens I've witnessed the male being hell bent on hurting the female for days afterwards. Even after the eggs are gone.
I keep a pair of rams in a 10 gal tank. I think that some of this aggresive behavior would be avoided in a 20 gal.
You can try putting a tank divider between the male and the female.
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