Ganlon (Berry #37), Salac (Berry #38), Petaya (Berry #39), and Apicot (Berry #40) Berries are supposed to be available in Colosseum. You will need PokéCoupons to get these berries on Colosseum. PokéCoupons are obtained in Scenario Mode, and also in Battle Mode for winning battles in the cups and the mountain. Every coupon that you get is worth a certain amount of points. The better that you battled, the more valuable the coupons will be. Each of these berries will cost 15,000 PokéCoupon Points.

Some berries are found on wild Pokémon in Fire Red/Leaf Green, but they aren't found in the soil patches like they were in Ruby/Sapphire. The soft soil was taken out of Fire Red/Leaf Green.

As for the Pokémon Contests, there are no Pokémon Contests in Fire Red/Leaf Green.