When you say kinda small tank are you referring to the 100G ?
Clowns when introduced one should be markedly smaller than the one that is first into the tank , the larger is the female and the smaller will go male if there is already a female in the tank.
Usually the male will do the funky tuna (shake ) to show submission , it is not 100% that the female will accept the "new" fish and could fight it till its death .(It has happened to me) Yes they can fight and yes the female can and sometimes will kill the male .
If the conditions are right it is possible that with in a year you could see mating behaviour .. But there is no set time on when they will mate and even if they will mate .. Alot of folks use a flat piece of tile for them to lay thier eggs on and move them to a nursery for hatching , the nursery is a safe place with nothing but the babies in there so that they dont become a snack . They will become fish food if not placed into a nursery tank ...
The filters are covered and there is very little flow . Food wise they eat rotifiers only as babies ... A good book for reading if you want to breed is Joyce Wilkersons clown fish . There is alot of special attention you will need to pay attention to as they are easy to breed but need special care to make it successful . Wet web also has great info on it . I have see several set ups done for breeding that take a 3 drawer set with 1 drawer for each age , I am not sure but I believe they are plumbed together ...Since I have never directly bred clown fishes (nor do I desire to at the moment ) This is all from what I have learned whilst keeping them..and reading about them