I just got a ten gallon tank to start raising some of the java fern starts I have in a 75 so I can put them in a 120 I will be setting up in a month or two. I just realized that I think one (maybe two) of the mickey mouse platy's I have might be pregnant. I put the filter for the 10 gallon in the 75 gallon to let it start to seed. I am planning on taking 5-10 pounds of gravel out of the 75 to put in the ten gallon. Once I put the filter and gravel into the ten gallon what should I put in it to keep it cycled until the platy fry are ready to move into it. What is the smallest stock I can put in with the seeded gravel and filter to keep the bacteria alive? Also right now the 75 has only been cycled for about three weeks. I don't want to take any gravel out of it until the platys are born (in a breeding box) I am planning on leaving them in the 75 until they are old enough to move. I am assuming right now it is too early to start taking gravel out of this tank since it hasn't been cycled that long. I thought this could send it into a mini cycle, or should I be okay to take some gravel out. I probably have between 75-90 lbs in the 75 so I will be taking out a small percentage.