I posted on craigslist that I'd be interested in trading a 30 gallon tank for a larger tank (just to see what interest was out there). Within 20 minutes I've had two responses, which is kind of surprising. Anyways, there is a guy who said he may be interested in trading a 60 gallon tank to me, but it's currently home to a bearded dragon. If he actually wanted to trade, is it possible to convert it to a fish tank without there being any dangerous toxins left in the environment?