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