The mudskippers (Oxudercinae) represent a subfamily on their own within the goby family (Gobiidae). One can observe all steps from “normal”, aquatic species (for example in the genus Apocryptes) to partially land-dwelling, amphibic species (Periophthalmus) within the Oxudercinae. Members of the genus Boleophthalmus don´t leave the water completely, but can be found in zones of the bank in which the water hardly covers the body.
Boleophthalmus are exclusively found in the tidal zone. During the flood they hide and cover on holes in the ground, during the low tide they search for food around their burrow. They feed with the extremely broad mouth on the upper layer of the silt and filter out all edible parts. The area around the burrow is heavily defended against conspecifics.
In the aquarium Boleophthalmus must be kept in brackish water in along term sight. Of course these fish are completely euryhalin (this means they can live in pure freshwater as well as in pure seawater); however, they are extremely sensitive against nitrite and nitrate in freshwater. Boleophthalmus can be fed problem-free with flake food which is quite equal to their natural food. The fish should be kept in a tank that imitates a bank with a shallow sand strand. It is not necessary to imitate the tide.
