The Two Spotted Goby darts around continually around in the water a few inches above the bottom often in patches. This habit as well as its markings make it easy to identify. It is reddish brown with pretty pale blue markings down its side. There is a distinctive black spot at the base of the tail and the male has a second black spot on it side immediately behind the pectoral fin. In summer time the fish sometimes gathers in large shoals.
This is a common species found all around the coast of Ireland in shallow water down to 15 to 20M depth. In the breeding season females usually lay their eggs around the base of kelp plants and the males take to the seabed to guard them.