The Tiny Goby
One of the most plentiful fish, yet one of the harder ones to notice, the goby's wonky eyes are always a delight to find on a reef.
Big Numbers, Small Packages
With over 2,000 species, gobies are one of the largest fish families, but they're certainly some of the smallest fish. Most are only 4 inches in length, and some are only 1 cm fully grown - the latter being one of the smallest fish in the world.
So Many Eggs, So Much Food
Their numbers are so many that 35% of the fish on coral reefs are some kind of goby. Considering that they lay over 5000 eggs at once, it's not surprising that there are so many of them. It's also unsurprising that they're a primary food source of a lot of larger fish.
Mostly Sea, but Sometimes Land
One of the coolest members of the family is the mudskipper. They can live on land for some time, using their pectoral fins as tiny legs. They breathe through their skin like frogs, and dig burrows to keep themselves moist.
No Mate, No Problem
Since female gobies prefer larger males, the smaller males have learned to be sneaky by using a behavior called kleptogamy. They may not have a mate of their own, but during spawning, they will lie in wait nearby and release their own sperm at the same time as the paired male.
Some species of gobies can wilfully change their sex. For instance, one of those smaller, less preferable males may choose to become female instead of engaging sneaky egg fertilization. A true example of "if you can't beat 'em, join 'em".
Opportunistic Sex Change
One species of goby are gender neutral until they meet an available mate. If they meet an available female, then they become male, and vice versa.
Some live symbiotically with other species, such as shrimp. The shrimp builds the burrow and the goby becomes a roomate. They maintain contact with one other, even warning the other in case of danger.
The next time you're on a reef, take a much better look at the coral and sand. You have likely looked over dozens of tiny gobies without realizing it. If you look closely, you may see some googly-eyed gobies peering back at you.