keyholeX2

I have a pair of keyhole chiclids that are keen egg layers, they do everything right until the 3rd or 4th day of the babys being hatched, then the babies dissapear and the parents chase each other and bite each others fins. The tank is shy of 100L, pH is about 6.8, no ammonia or nitrate, and they also have 2 bristlenose plecys with them, they have a large eheim canister filter attached and get chiclid granuales and tropical granuals, along with the algae discs. Have you got any idea what is happening??

i Brought 2 bristlenose plecys, and they were the same size, now one is about 10cm and the other one is still about 4cm it hasent growen??? Any ideas why this would happen??