There are 3 land parts, one bigger of sand and grass, one island what you can see at this picture and one swamp pool but the hippos don't use the last.
In my opinion, there is enough land for the hippos, they are with 3 now and the maximum that Antwerp will hold are 5.
I saw them in the swamp pool not long ago! They enjoyed it a lot! Great picture, I have a similar one, also from your point of view with Imani on the little island .
@Marc: You saw them at the swamp pool? Lucky one ! I know about one time when the exhibit was brand new. When I speak other people, they said also they have never seen it or one time at the best.