The female will have no interest in the kids once she laid the eggs. The male will guard them for about 2 to 3 weeks until they have hatched and used up their egg sacks. But he won't be aggressive. He will just block the other fish from getting at the fry. When they used up the egg sacks, he lets them go out in the tank. Your rams will eat them. The corys will not and with the tetras it depends on the size and type. The pleco fry will be about .7 cm when the dad lets them out of his "cave", so I really only see the rams as a problem, unless you have a large type tetra. Most LFS will take pleco fry when they reached about 1.5 inches, which they will reach in about 2-3 months. A batch can have anywhere from 15 to 100 fry, but a first batch is often infertile and just a practise run. Once they start, however, they usually keep going. First surviving batches tend to be smaller than subsequent ones. Again there are exeptions to this rule, my first BN pleco pair that bred had 107 fry and all survived. I counted them as I sold them and shipped them out. This may not have been their first batch as I had larger fish in the tank with them and had to move the cave with the fry and dad to another tank for this batch to make it. Today I have all my male Bns in one tank, the females in another as I ran out of space for the kids pretty quickly.