Approach it slowly, it'll go better, and work out best in the long run..tank sizes depend entirely on your plans. Wait for a Petco or similar buck a gallon sale. Buy large ones from Craigslist..larger tanks for display or growouts, smaller tanks for breeder's and small fry...drilled or undrilled is a topic unto itself. When I worked, drilled worked best for me...now retired, undrilled satisfies me better. WC's can go a few ways, but they all rely on pumps, so look at hevy duty water and air..