I love that you made a whole little dedicated reptile house for them! That's a great way of making something more to fit the whole zoo, instead of just a lonesome little exhibit box... x') Remember to put up education signs! And maybe give the building a name? I suggest Viper Vivarium :) Another little extra touch might be to section off an area surrounding the building with some appropriate foliage and terrain work, kind of as if you were making a habitat for them, but it's obviously just a larger "planter" area to boost the general view and theme around the building.

Can you Upload Planet Zoo Alphabet Zoo W is for Wild Water Buffalo?