Gobies (Gobiidae) and blennies (Blennidae) are two large groups of fish. All are bottom dwellers, quite small in size; the largest of those shown here is max. 30cm in length, and most are 10cm or less. Although gobies and blennies are quite similar in appearance, blennies have shorter, blunt heads. Blennies and gobies can be seen on every dive or snorkel if you look carefully!