Hi Loughrea
That tank would be excellent for a breeding tank.
It has pea size gravel, and decorations, should I keep these in or remove them?
And it is full of water, do I need to remove some water?
When the corys have spawned, you do need to move the adult fish out because, while bronze corys don't usually eat their eggs, they can't seem to tell their fry apart from other food they find at the bottom.
Constantly moving the adults, won't hurt them?
The good news is that, since you will then have a bacteria laden filter, you can move that out into still another tank for them. The fry tank can easily be run with an air pump and an airstone or two while the eggs are hatching, then a sponge filter and finally a box filter.
What is a sponge filter and a box filter?
One of the things needed to keep the fry healthy and growing at their maximum potential is daily small water changes. This removes the uneaten food and bacteria that could grow on it, and the waste products these tiny fry produce is little. As they begin to grow, beneficial bacteria will begin to colonize the sponge filter and the tank will gently cycle itself. By the time they are large enough to keep from passing through the slots on a box filter, you can add one of those to filter out solid particles.