according to www.aqadvisor.com
yes you are, and this is with a 2.5 gallon tank:
Note: Betta [Male] may jump - lids are recommended.
Warning: Corydoras C079 is not recommended for your tank - it may eventually outgrow your tank space, potentially reaching up to 2.2 inches.
Warning: At least 4 x Corydoras C079 are recommended in a group.
Recommended water change schedule: 65% per week. (You might want to split this water change schedule to two separate 40% per week)
Your aquarium stocking level is 167%.
Your tank is overstocked. Unless you are an experienced aquarist who can meet the maintenance/biological needs of this aquarium, lower stocking levels are recommended.