How do you get an entrance on marine park empire such as a ladder or gate because my octopus need food and it says theres no entrance

All u have to do is go into the fences and there SHOULD be a gate there, and click on it and then put ur mouse over the gate, and then click, and that should work.... but i have not played the game in a long time so that might not be right, but u should give it a try anyways!!!