I want to make a small 2.5 gallon or 5 gallon cherry shrimp tank so I can breed them out before putting them in my 29 gallon. I was wondering first which size to go with? Second if I add a sponge filter from my 29 gallon will that be enough filtration and bb to cycle the tank instantly and keep it filtered? I also plan to steal some plants from the 29 gallon. If I go with the 5 gallon I might eventually try introduce my betta to the tank as I have him in a divided 10 (treating him for velvet) and I actually wish to down size the tank and put my other betta up for adoption.