While you are waiting to get the new tank get a 70 gallon rubbermaid water trough and a couple large sponge filters and heaters, it will cost under $100 total. Keep the pacu in that for the time being, they measure 24"tall, 40 1/2"long and 32" wide and are very sturdy. It would provide a resonable home forthe pacu while waiting and that would also improve conditions for your other fish, A sheet of eggcrate light diffuser can work as a lid and all the stuff can be reused for other projects once you get the large tank running.