Blenny & Goby

Group 8: Small, Elongated Bottom Dwellers

Blenny & Goby

Group 8 - Small, elongated bottom dwellers : The small bottom dwelling fish often make up the most interesting fish to watch during your dive. Their approachable nature and interesting behaviors make them great fishwatching finds. Blennies tend to be slightly larger than gobies, but are most easily recognized by their curved body posture and expressive faces. Gobies, though similar in their habitat requirements, tend to sit flat and straight on the bottom. The jawfishes actually live in a burrow in the sand that they excavate and maintain.

Bluespotted Jawfish (boca manchada azul, Opistognathus rosenblatti)

Jawfish
are some of the most fascinating bottom dwellers to find and watch during your dives. They can be found hovering vertically just above their holes in a sandy or rubble bottom. As divers approach, the jawfish will back down into their holes tail first to disappear. Males of the species incubate eggs until they hatch by holding them in their mouths to prevent predation. The bluespotted jawfish is covered in blue spots. (Max. size 4”)

Browncheek Blenny (carillo moreno, Acanthemblemaria crockeri)

This
charismatic blenny will often be found inside abandoned barnacle shells. The obvious large, brown mark on its cheek is the key characteristic to identifying the browncheek blenny. The bush-like cirri over each eye confirms that it is a blenny not a goby. (Max. size 2.5”)

Choose another fish Category

1. Disks and Ovals / Colorful

The first category of disk and oval shaped fish are very important to learn. They are colorful, large and very obvious and the three main families that make up the group can be found on almost every dive.

2. Silvery Fish

Silvery fish have many different family members, though we will look at just a few representatives. As opposed to the colorful butterfly, angel and surgeonfish, the silvery fish tend to blend in better in open water and are usually not found near the colorful bottom.

3. Sloping Head / Tapered Body

This third group of “fish-like” fish, are very important to learn. The are common on most dives and are also highly sought after as food fish. It is especially important to monitor these fish to provide data for fisheries management. Snappers can be very difficult to tell apart from the similarly shaped grunts. One helpful hint is to look at their tails. Snappers tend to have straight, flat tails. They are also known for their habit of snapping their mouth open and shut when caught on hook and line. They have very sharp canine teeth that can provide a nasty bite to the unsuspecting angler. Look closely on your next dive and you may see the small teeth protruding from the side of the mouth. Grunts on the other hand, have slightly notched tails. They get their name from the grunting sounds they emit when threatened. These sounds are created by rubbing together bony teeth plates located in the back of the throat. Since the teeth are in the throat, a diver will never see protruding teeth on a grunt, only big blubbery fish lips.

4. Small Ovals / Damselfish

While divers tend to first notice the larger, more obvious fish on a dive, after a short while the challenge to find new species leads them to change their search image to look for smaller, previously unnoticed fish. Generally, the first new species a diver will encounter will belong to the small oval shaped group. This group is broken into the damselfish and their close cousins the chromis. Damsels are like the surgeonfish in that they eat algae. They do not roam around grazing, but rather tend to small algae gardens like a farmer. These areas are guarded fiercely as the algae farm is the damsels food source. For that reason you can think of the damselfish as not just territorial, but Dam- selfish with its territory. Many damselfish have distinctly different colors as juveniles, often being much brighter and more colorful when they are young and becoming drab with age. (much like us humans!) For this reason, the juveniles have been heavily collected for the aquarium trade and are under heavy fishing pressure. As part of the REEF Fish Survey Project, divers are asked to monitor the juveniles and adults separately in two of the damselfish species – the Cortez damselfish and the giant damselfish.

5. Heavy Body / Large Lips

Heavy bodied, large lipped fish belong to the seabass family. We tend to refer to the larger seabasses as groupers and the smaller seabasses as bass or basslets. These fish are extremely important food fish and are under increasing threats from heavy fishing pressures. Monitoring these fish can help provide valuable data to aid in their protection. Most seabasses are hermaphrodites, meaning the same fish will be both a male and a female during its lifetime. The groupers are all born female and later change sex to become male. Most large groupers also congregate each year to spawn at a specific location, making them easy targets for emerging positioning and fishing technology.

6. Swim with Pectorals / Obvious Scales

The fish in this group all use their pectoral fins to swim with rather than the traditional tail swimming of most other fish. The scales are also quite large and obvious. These fish can also be hermaphrodites, like the groupers, with some fish changing sex and others staying the same. Intermediate and adult fish often have very different appearances compared to the always-male terminal phase. This means learning two colors to be able to ID the same species of fish. Most of the pictures shown in this curriculum are terminal phase males, unless noted.

7. Redish / Big Eyes

This group of reddish fish is normally not seen during day dives due to their nocturnal nature. The reddish color helps them blend in at night and the large eyes help them to see better.

8. Small, Elongated Bottom Dwellers

The small bottom dwelling fish often make up the most interesting fish to watch during your dive. Their approachable nature and interesting behaviors make them great fishwatching finds. Blennies tend to be slightly larger than gobies, but are most easily recognized by their curved body posture and expressive faces. Gobies, though similar in their habitat requirements, tend to sit flat and straight on the bottom. The jawfishes actually live in a burrow in the sand that they excavate and maintain.

9. Odd-Shaped Bottom-Dwellers

This category of fish is made up of families and species that didn’t quite fit anywhere else due to their unique body shapes.

10. Odd-Shaped Swimmers

This group of fish contain families that are unusual in their shape, but are swimmers rather than bottom dwellers.

11. Eels

Though looking like snakes, eels are fish. There are several different types of eels, and we will look at two – garden eels that live in burrows in the sand and moray eels. Moray eels have a bad reputation mainly due to the constant opening and closing of their sharp toothed mouths. However, this is not a threat to divers, as this action pumps water through their gills. Most eels are actually very shy.

12. Sharks & Rays

Even though the sharks and rays are cartilaginous (their skeletons are made of cartilage instead of bones), they are still referred to as fish and count during our surveys.

FUN Facts

5 Fun Facts - Blennies & Gobies

Blenny is a common name for many types of fish, including several families of marine, brackish, and some freshwater fish sharing similar morphology and behaviour. Six families are considered "true blennies", grouped under the order Blenniiformes; its members are referred to as blenniiformids. About 151 genera and nearly 900 species have been described within the order. The blenniiformids are superficially quite similar to members of the goby and dragonet families, as well as several other unrelated families whose members have occasionally been given the name "blenny".

Goby is a common name for many species of small to medium sized ray-finned fish, normally with large heads and tapered bodies, which are found in marine, brackish and freshwater environments. Gobies are members of the Gobiidae family, which is a species defined by their spiny pelvic fins that are fused together to work as a ventral sucking disk. This trait allows gobies to adhere to terrain or objects in situations of heavy currents (sometimes even climbing up waterfalls). There are over 2,000 varying species of goby, examples include clown, cleaner, watchman, sand sifting, etc. Gobies vary from 25-75 mm, come in an array of camouflaging hues such as blacks, browns, yellows, oranges, greens. Another characteristic unique to goby is its vertical markings.

Mimicry: Many blennies demonstrate mimicry of other species, such as Aspidontus taeniatus. This mimicry allows the blenny to get up close to fish that would normally let Labroides dimidiatus (the bluestreak cleaner wrasse), clean them. The blenny then takes nips or larger bites out of the unsuspecting fish.

Masters of Camouflage: Blennies are the chameleons of the sea. These small, elongated fish are experts in blending into their surroundings. Some species, like the Redlip Blenny, are known to mimic the appearance of coral or sponge, making them practically invisible to predators. But their camouflage isn't just about survival – male blennies also use it to attract mates by showing off their vibrant colors in hidden nooks and crannies.

Battle of the Blennies: Blennies have a unique way of resolving conflicts – they engage in "jaw locking" battles. When two males vie for territory or a mate, they lock jaws and engage in a pushing match. What makes this showdown even more extraordinary is that the blennies often end up with their mouths wide open, showcasing an array of impressive teeth. It's a peculiar spectacle in the underwater arena that's both amusing and a testament to the resourcefulness of these little fighters.

Skilled Architects: Gobies are the construction workers of the underwater world. These fish, often diminutive in size, are renowned for their fascinating habit of building homes out of sand and debris. The Jawfish Goby, for instance, digs intricate burrows in the ocean floor where it seeks refuge and raises its young. Gobies are not only skilled architects but also committed parents, fiercely guarding their homes against potential threats.

Goby Gossip: Gobies communicate in a rather unconventional way – they click! These fish produce clicking sounds by grinding their teeth together. This behavior serves various purposes, from signaling territory boundaries to attracting mates. Some gobies even synchronize their clicks with their neighbors, creating an underwater symphony that's both mysterious and captivating.