not to be a promoter of small tanks but i used to bred my main couple in a 40g breeder, then take them out when the eggs were fertilized and let the the fry grow out in that tank.
i see nothing wrong with it, but u have to make sure the male will take to the female. have hiding spots that only the female can fit, or even seperate them in the tank until her tube drops, the he might be more reciptive to her, but if u don't take any of these steps ur male will rip ur female apart. fh are generally loners and u have to ease them into breeding