No, some ways you can earn tu are:
-playing games
-stocks (once you have more tu)
-selling pets or items-- if you are a rancher, you can sell pets in your rancher shop, and if you are a merchant, you can sell items in your merchant shop. If you are a merchant but you want to sell a pet, you can use the Sales and Trades forum board or advertise on the Shoutbox (if you are old enough to use it) and viceversa.
-sell hatches-- once again you can advertise this on forums are the SB, but the idea is that if you haven't used your hatches, a user can send you eggs and 100k per hatch, and you use your hatches and give the person the pet that is hatched.