Here is the full list of all 30 Aquarium Designer achievements.
Keep at least 3 different fish or plant species alive for a week in the Realistic Mode aquarium
Get all the achievements
Get 100% of points for 20 contracts
Complete 100% of contracts
Feed fish 300 times
Get 100% of points for 15 contracts
Unlock 100% of store items
Complete 60% of contracts
Get 100% of points for 10 contracts
Unlock 80% of store items
Place 300 rocks in the aquariums
Complete 30% of contracts
Get 100% of points for 5 contracts
Unlock 60% of store items
Allow 300 fish to die
Allow 300 plants to die
Unlock 40% of store items
Create 9 fish tanks in Casual or Realistic Mode
Clean the fish tank
Make the fish tank dirty
Unlock 20% of store items
Complete the second contract
Complete the first contract
Start your first contract
Remove 300 things from the aquariums
Create your first fish tank in Casual Mode
Spend 10000$ money
Change the filter for the first time
Place 100 fish in a single fish tank
Create your first fish tank in Realistic Mode