Just took some more photos of my native goby tanks. Ok, native to Dniester River))) I have 3 freshwater species of gobies in there: monkey goby, round goby, and toad goby. Toad goby ( Mesogobius batrachocephalus) is the largest one, but he only comes out when he is hugry, so I couldn't get any photos of him this time. However, I got a bunch of pictures of my monkey gobies and round gobies.
Monkey or sand goby (Neogobius fluviatilis) is showing his chubby face
Two monkey gobies and a round goby (Neogobius melanostomus) hanging out together.
A profile view of my large sand goby
Larger and smaller monkey gobies together near their rock cave)))
Another cool view of the gobies
2 monkey and 2 round gobies hanging out. round gobies are more brown and have a rounder face
Here you can clearly see the difference between monkey goby and a round goby. Plus round gobies have the signature black spot on their dorsal fin
If you are wondering how to keep round gobies and monkey gobies in an aquarium, well, it's very easy. Mine are wild caught. I caught them myself. They eat anything, including dry food, but prefer blood worms and frozen shrimp. Both round gobies and sand gobies can be kept in any type of water. By that, I mean, they can be kept in pure freshwater, brackish, and in fully marine conditions. I keep my in pure fresh. They have started eating within hours of being caught. For those of you living in US or in American occupied territories (Florida, Alabama, Kentucky), these gobies are considered invasive species. So you can't legally keep them in aquarium there. You might get a serious fine if they catch you.