Currently they are all in the 125 gallons (I know that is too much). I also have a 75 and 55 gallon that are not setup yet due to moving. Once the other tanks are setup the undulated and possibly another fish I don't own yet are going in the 55 gallon (fish only tank). The niger, 2 tangs and 2 gobies will go in the 75, and the rest will stay where they are.