Yellow Watchman Goby makes an adorable addition to your collection. It invariably forms an endearing bond despite its shy demeanor.

Do not be surprised if you catch yourself glued to your community tank, awaiting a glimpse of this beautiful, watchful fish.

Its vibrant yellow body with blue dots and transparent ray fins give it an ornamental, bejeweled look that steals the show in any marine aquarium.

It is easy to care for, peaceful and can fit into small aquariums, making it desirable.

This article is about caring for the yellow watchman goby and some interesting facts and myths about it.

Yellow Watchman Goby Species Overview

Generic Facts
Scientific Name Cryptocentrus* Cinctus
Other popular names Yellow Watchman Goby, Sulphur Goby, Yellow Prawn-Goby, Yellow Shrimp Goby, Banded Prawn Goby
Family Gobiidae
Origin Western Pacific
Average Life Span Up to 5 years
Adult Size Up to 4 inches
Type Marine/Salt Water
*The word Cryptocentrus is derived from two greek words – Kryptos = hidden +  kentron = sting

Identifying Gobies

Yellow Watchman Goby is a Goby fish. What makes gobies unique?

The below image shows different fish fins.

While the shapes (of all fins), numbers (of dorsal fins), position (of the pectoral fins), and sizes may vary, all fishes have them. Most fishes have single Dorsal, Anal, and Tail fins but two pelvic fins (one on each side).

Against this, the below image depicts a Goby.

Gobies are

  • Long, ray-finned, and small (up to 4 inches).
  • They have thick lips, protruding (frog-like) eyes, slanting (flat) heads, and round tail fins.
  • Their pelvic fins are merged into a suction disc. Thus, they have a single pelvic fin.

Habitat and Origin

Yellow Watchman Goby is a marine water fish from the Western Pacific Ocean. It thrives in lagoons and coastal waters up to 25 meters in depth.

It builds its burrow in the sand, in an environment with corals and rocks (to hide), and fiercely protects it. Hence, it typically sits at the burrow entrance with its head out or swims nearby.

At the slightest sign of danger, it swiftly retreats into the burrow. Thus, it is always hiding in its environment and constantly on guard.

In the wild, it automatically teams up with the pistol shrimp. This shrimp has poor eyesight and relies on the Yellow Shrimp Goby to evade predators. In return, the pistol shrimp makes a burrow for the goby and maintains it tidy. Both reside in the same house.

The pistol shrimp follows the guardian goby everywhere, using its antenna to track it, and retracts into the burrow or hides along with the goby when in danger.

This symbiotic relationship between the yellow watchman goby and pistol shrimp continues in the home aquariums. They are often kept together in captivity. Watching their teamwork is a delight to the eyes.

It explains how our goby got some of its popular names listed earlier.

The term watchman goby refers to many species of gobies, which form a similar relationship with the pistol shrimps.

Below is a video of a pistol shrimp introduced just 30 minutes into the same tank and the duo bonding. Notice how the left antenna of the pistol shrimp does not move away from the goby.

Life Span and Size

They live for two to three years in the sea, but in captivity, they even live up to eight years with proper care.

They grow up to 4 inches in size on average.

Physical Appearance

Yellow Watchman Goby Physical Appearance

As depicted above, the yellow watchman goby has a vibrant yellow body, explaining its name Sulphur Goby. 

Its mouth is drooping and has a frowning expression. It has frog-like, protruding eyes. The former part of its body and the two transparent dorsal fins have random blue spots. Its round tail fin is semi-transparent with yellow lines, whereas the ventral fins are opaque yellow.

The fish has slightly dark, broad bands of the same color on the later part of its body, lending its name Banded Goby. As discussed earlier, its pelvic fins are fused into a suction cup. It helps the goby to maintain its perching position (as in the left image) at its burrow entrance.

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It has no scales on the head but small scales on the body. It comes in yellow, orange, and gray colors.

Color Changes

Yellow Watchman Goby Color Changes

Many have reported that their yellow watchman goby turned its color from yellow or orange to gray.

A few regained their original colors, while a few did not.

Also, note the dark bands on the later part are noticeable in this image of a gray goby.

A report indicates that gobies can change colors according to their background to camouflage themselves in self-defense.

Their color fades when they are stressed. However, it normalizes as they feel safe again. It is valid for all.

Few suggest that they become gray as they age. However, all do not display this permanent color change with age, breaking the myth.

Interestingly, some varieties of gobies can change colors along with their sex. But the yellow watchman goby does not have this ability. Its color changes are not associated with gender or maturing.

Typical Behavior Patterns

  • Yellow watchman gobies are shy, bottom-dwellers.
  • Their tank must be covered with a lid, as they tend to jump out.
  • They are peaceful with other fishes but get territorial with same-gender species of their own.
  • They perch at their burrow entrances and do not swim farther.
  • They do not allow anyone to come close to their burrows.
  • The only exception is the pistol shrimp, with whom they share a symbiotic bond (refer to section 1.2 for details).
  • Thus, they love to be alone, in a pair, or with a pistol shrimp.
  • True to their name, yellow watchman gobies are always alert and sensitive to their environment. They will flee into their burrows if they sense danger.
  • Their color becomes pale if they are stressed. Besides, they randomly change colors (refer to section 1.5).
  • They display parental instinct by depositing eggs in caves or on rocks and protecting them till they hatch.

Sexing

The only known difference is that a female yellow watchman goby is plumper than her male counterpart. There are myths about different colorations. Other things being the same, pairing a larger one with a smaller one might work out, assuming the larger one is a female.

Another behavioral indication can be if they co-exist. If they are the same gender, they will be aggressive with each other, or will live peacefully in the same tank and even the same burrow. This is possible to check only after adding them.

How to Select

They are saleable from 1 inch onwards. Their price begins from $21.00, depending on their size, availability, and offers.

Yellow watchman gobies are available in most pet-fish stores for sale. Buy from a trusted source.

Try to buy captive-bred species, as they can adapt to a captive environment. Use their complete and correct name while purchasing, as there are many species of gobies called watchman gobies. A yellow-headed sleeper goby is also a different species.

Check their appearance (or photos) before ordering to ensure you buy the correct one.

Since it is difficult to differentiate their gender, buy a single goby or a pair from the store. They will ensure you get them right.

Avoid purchasing from newly arrived stocks or small sizes, as you cannot be sure about their health and responses to a captive environment.

Check them completely for any physical discrepancies before buying/upon receipt, before acclimating them. Follow the vendor’s instructions to the tee to avail of the after-sale warranty.

Yellow Watchman Goby Care

Care Overview
Care Level Easy
Diet Omnivorous
Temperament Non-aggressive with other fishes, but territorial with same-gender species of its own
Breeding Difficult
Social Gels with other fishes
Tank Level Bottom-dweller

What do They Eat?

In the wild, the yellow watchman goby eats anything that can fit into its mouth. It is a slow eater. Initially, it may refuse food for one or two days. Try leaving some at the burrow entrance or where the goby can find and eat it.

How and What to Feed

Since it is a bottom-dweller, use sinking foods that can reach the bottom. It cannot compete for food with other fishes (including its pistol shrimp buddy). So feed them before feeding the goby. The pistol shrimp and goby will eat leftover food from the substrate.

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Feed twice a day for two to three minutes and wait. Check if your yellow watchman goby is accepting it. Do not overfeed or drop too much excess food, as it will contaminate the tank water quality.

You can feed Marine Fish Flakes, Fish Pellets, Live Foods like Shrimp (Brine and Mysis), Bloodworms, Squids, and Frozen Foods after defrosting. Moisten dried foods slightly before feeding.

Keep the diet varied and nutritionally rich. Use quality food to avoid infections through food.

Breeding

Challenges in Captive Breeding

The challenges in breeding yellow watchman goby in captivity are:

  • It is hard to pair them. Many buy a pair from the vendor, hoping to breed them.
  • Their spawning size and triggers are unknown. Hence, owners rely on mating behavior (the pair constantly moves into shelter and chases each other) and keep checking their burrows or caves for eggs.
  • If they suddenly find the eggs, they do not know how to care for them, resulting in high mortality rates.
  • The readymade food for newly hatched fries is expensive and involves more investment and higher delivery times (sometimes). Before the food arrives, the fry(s) might die.
  • Owners have to rely on shared knowledge in online forums about breeding them, with very few success stories doing rounds.

Learnings from Successful Captive Breeding

Below are some pointers about successful captive breeding by an owner.

This owner managed to breed yellow watchman gobies in captivity.

  • All his female gobies were gray, but he later confirmed successful pairings between two yellow gobies and two gray gobies by other hobbyists.
  • Besides, he cited random color changes in gobies as they grew.
  • He received a pair from his friend and placed it in a 20-gallon tank with some artificial decor and PVC pipes.
  • The pair spawned within 12 days. They transferred the lot into a hatching tank.
  • The eggs took four days of incubation to hatch.
  • He used rotifers (which he used to breed clownfish) to feed the tiny-miny hatched eggs.
  • According to him, there is no way to determine if the hatched eggs ate the food unless they survive for the first four days.
  • This and many more lots were a disaster.
  • He used a microscope and understood that the newly hatched egg was too tiny and needed especially small food to fit into its mouth.
  • The ready food available online was expensive, involved high delivery time, and was not in sufficient quantity.
  • He found a food called clam trochophores in a local store. It is the larvae-development stage of an oyster or clam. However, he could not preserve it or coincide its availability with the breeding cycle of his gobies.
  • After further research and networking, he received a vial of B. Rotundiformis cysts from a source.
  • He hatched this vial and began culturing it in-house.
  • It took 13 spawns and 12 months to succeed. The culture of S-strain rotifers worked for the newly hatched goby eggs.
  • He moved to slightly larger food (L-strain rotifers) after 14 days of hatching.
  • From the 28th day, he started feeding newly hatched brine shrimps.
  • He used a microscope to capture the following images:

The image of newly hatched eggs of clownfish and yellow watchman gobies.

Goby eggs are comparatively smaller. Hence, it needs small-size food to fit into its mouth.

Below is a rare video showing a pair of Yellow watchman goby with the egg larvae captured by another hobbyist.

Diseases

Yellow watchman goby is sturdy and not prone to marine fish diseases.

However, you need to take proper care of its diet and manage the tank environment efficiently to ensure it remains healthy and happy.

Keep an eye on your yellow watchman goby and other tank-dwellers for any physical or behavioral changes.

If you notice anything unusual, read more about common diseases in aquarium fishes. Consult a vet for proper diagnosis and care.

Acclimation

Quarantine and deworm your newly purchased fish before adding it to the main tank. This will eradicate the chances of bacterial or parasitic infection coming from outside.

Acclimate it so it can adapt to the main tank water parameters without stress or complication due to water changes.

Yellow Watchman Goby Tank Requirements

Tank Specifications Overview
Minimum Tank Size 20 Gallons
Water Temperature 72 – 82 degrees F/22.2 to 27.8 degrees F
Salinity 1.02-1.025
PH Level 8.0 – 8.4
Water Hardness 8.0 – 12.0 degrees dKH
Reef Safe Yes

Tank Size

Since the yellow watchman goby gets aggressive with same-gender species of its own, add a single goby or a pair. It is a small fish. Hence, a 20-gallon tank is sufficient to house a single goby.

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Select an appropriate tank size based on the space requirements for the goby(s) and other tank-dwellers you choose or already have.

Avoid overcrowding. There should be enough free space for all the fish to grow and swim.

The tank should be broad and not tall. It should have a tight lid, as gobies are jumpers and tend to escape. 

Tank Setup

A tank setup resembling its natural environment helps to keep the goby healthy and happy. It also promotes breeding, if possible.

It is reef safe. Hence, a reef aquarium like FOWLR (Fish Only With Live Rocks) or a marine aquarium with rocks, corals, and sandy bottom is an apt choice.

Substrate

Yellow watchman goby digs a sand burrow and remains hidden in its nest most of the time. It also feeds on the bottom leftovers.

Hence, a thick layer of sand is the best substrate. Ensure the sand is not too coarse.

Lighting

Use reef-safe lighting. It will enable you to enjoy the view, observe them, and enhance the natural beauty of your yellow watchman goby to its fullest.

Decor

Plenty of corals, rocks, and caves will mirror the yellow watchman goby’s natural habitat with sufficient hiding spaces.

Use live or artificial rocks and corals with clay pots, PVC pipes, etc. Make your aquarium colorful and decorate it tastefully. Everything in the tank should have smooth, rounded edges and surfaces.

All openings should be large enough to allow tank-dwellers to swim through without hurting themselves or getting stuck, even after they grow.

Oxygen and Filtration

Use a standard filter with an air pump and air stone (if needed) suitable to the tank size. Yellow watchman goby prefers slow-moving to still water flow (as in the bottom seawater). Adjust the water flow accordingly.

Use biological and mechanical filters to clean the tank water quality and minimize ammonia and nitrate levels.

Tank Mates

Yellow watchman goby will instantly pair up with its mated partner and a pistol shrimp. Besides, they will do well with other small, peaceful, non-interfering fishes.

Goby eats anything that fits into its mouth. Avoid adding large fishes that might feast on your goby or small fishes that might fall prey to the goby. Fin-nippers are a big no in the same tank.

Consider other small, peaceful fishes that occupy different tank levels. It will ensure they do not interact and bring all tank levels to life. However, they should share similar tank water parameters.

Many hobbyists successfully added bicolor or tail spot blenny and a yellow watchman goby to the same tank, while some reported tail spot blenny eating and harassing their goby.

The tank size, decor that separates them, and the areas they occupy (one on the rock and the other in the sand, or both on either side of the same or different rocks, etc.)  might have helped.

Do not take chances with your favorite pet fish.

Frequently Asked Questions (FAQs)

Is the yellow watchman goby a sand sifter?

Sand-sifting gobies sift the sand using their gills. They extract the nutrients from the sand and throw them out of their system using gills.

This process of sifting sand (for feeding) cleans the sandy bottom. Hence, a sand sifter (like the diamond watchman goby) is added to an aquarium to clean up the sandy substrate.

Yellow watchman goby is not a sand sifter. It uses its mouth to spit excess sand out while making and maintaining its burrow in the sandy bottom. It eats the leftovers from the sandy bottom. But it does not sift the sand through its gills like a true sand-sifting goby.

Can a diamond watchman goby and yellow watchman goby live together?

Yes. As long as they both have separate burrows and the tank size and decor are apt to keep them away, there should be no problem.

They will get territorial and drive away the diamond goby if it comes closer while sifting the sand. It is the only possible interaction.

An owner reported that the duo got along well and even stayed in the same burrow in his home aquarium. Quite a sight to behold!

Use the tank decor (like rocks) to demarcate their areas smartly.

Conclusion

If you are new to the hobby or saltwater aquarium, consider adding an adorable yellow watchman goby. Many experts also look forward to owning it.

You will love watching this marine beauty change color or guard the pistol shrimp. Looking out for this goby while it is hiding and watching you is a game you will enjoy. Soon it will gather enough to feel safe in your presence and bond with you.

It will engage your guests, family, and friends alike. When are you adding a yellow watchman goby?

We wish you a happy fish parenting time!

About the Author

Victoria Lamb

Victoria is a freshwater aquatics specialist, fish keeper, and amphibian enthusiast. She has had more than 6 years of experience caring for aquariums and keeping several fish species, and her home boasts of 3 aquariums and a garden pond. Her goal is to educate fish owners on raising healthy and happy aquatic pets.

Career Highlights:

  • Has worked with several aquarium manufacturers as a consultant
  • Organized and hosted workshops on freshwater fish keeping at retail stores, educational facilities, and libraries
  • Released content for the amphibian community through her writings

Educational Highlights:

Bachelor of Science in Animal Behavior and Welfare

  • University of Lincoln, Lincoln, UK (2014-2018)

Writing Experience

Victoria has done ghostwriting for many aquarium and pet websites in the past. She has also worked for Canada's largest natural health magazine- ALIVE, with 300,000 monthly circulations as a freelancer. She had six published articles on animal behavior and welfare during her graduation for her thesis.

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