Minimum Tank Size 50 Gallons
Water Parameters 72-78 F, pH 8-8.4, Salinity 1.020-1.025
Aggression Peaceful, but will eat smaller fish
The Engineer Goby is unlike any other goby as it is in fact not a goby. These guys are a member of the Pholidichthydae family and exhibit a mixture of eel and jawfish natures. They are given the name ‘Engineer’ as they will frequently be building burrows by digging in the sand bed, even after establishing a home. When they are not digging Engineer Gobies can frequently be seen hiding under rocks or searching for foods.
In the home aquarium they will be peaceful fish despite their large size, however they will eat other fish that fit into their mouths. They are best introduced to the tank with one or more Engineer Gobies at the same time, however as they mature they require much more space and are frequently kept individually. They are however social fish and enjoy living in pairs/groups.
Special Tank Needs
It cannot be understated how much the Engineer Goby digs. When the tank is not made with this in mind you can expect rocks to frequent be toppled. To combat this you will need to place the rock all the way at the bottom of the tank, with its largest side/one of the more stable sides against the bare glass. This must be done with all rocks to avoid any avalanches.
Additionally the frequent burrowing, which requires a lot of sand displacement, can easily bury low placed corals. While not a lot can be done to prevent this issue, other than avoiding specific corals entirely, you can attach the corals to rocks, burying the bottom of the rocks to the bottom of the tank. This will create a pedestal like surface that will keep the coral from being toppled over and buried under the sand. The coral will still be able to be covered, however only by a large, hard to miss sand dune. If you see this you can easily find the coral, rather than sifting though sand like a diamond watchman goby.
Diet & Feeding
The Engineer Goby is extremely easy to feed and will accept almost any food offered to them. They are carnivores, so you will want to choose a mostly meaty diet. Still you will want to sneak in extra greens to promote good health.
Engineer Gobies respond well to both large and small foods. Unlike eels they have fairly good eye sight and will eat out of the water column with ease. When feeding they will frequently have a jawfish behavior of swimming out of their burrow, grabbing a piece of food and returning home. This will go on for awhile until the Engineer Goby has had its fill.
While the Engineer Goby is not inherently aggressive, they can get more aggressive as they mature. This combined with the creation of multiple burrows and their large size can cause issues when adding new fish.
To combat this you will want to add only semi matured fish or older fish. The key here is that tank mates must be larger than the gobies mouth. Juveniles or small fish will frequently go missing when placed in the mature Engineer Gobies tank. Additionally you will want to avoid any burrow seeking fish. Those who venture into a well established Engineer Gobies den can quickly find themselves harassed until they leave. While this will not kill the fish it will add on plenty of extra stress which can lead to the fishes demise.
Breeding the Engineer Goby has been done several times in the home aquarium and is generally not too difficult. The main issues are:
- Getting a mated pair
- Raising the fry
To get a mated pair aquarists will typically get a few extra Engineer Gobies, as there is no way to differentiate a male and female goby. The common number of gobies chosen is typically four or five. Four gobies will give you a 7/8 chance to have at least one of each gender while five will make the odds 15/16. Because of the next step I highly recommend four if you go this route.
Engineer Gobies will only breed after they have matured. Seeing as the Engineer Goby can live well over four years, with some aquarists even reporting breeding in the 6th year, you will have to keep the gobies together for quite awhile. Those looking to breed them quickly must find matured pairs, as newly introduced mature gobies will rarely get along.
The gobies will need a large tank, no less than 150 gallons. They need plenty of space, rocks and burrows for the breeding to take place. Once the pair is old enough and have found an acceptable home they will begin spawning. They do not spawn frequently but do have large numbers.
The eggs are laid in large sticky clutches that will remain in the parents burrows for a few weeks after hatching, with the parents bringing them food and defending the burrow. After this time the parents will usher them out of their home and even begin eating them. Remove as many fry as possible before this happens. A tank with plenty of rock and some pre-dug burrows works well for a new home.
When the fry are removed the should be fed rotifers and baby brine shrimp frequently. Brine shrimp should be the less common meal, as this will frequently become the only accepted food. This will lead to the frys death due to low nutritional value.
Once the fry are larger you may begin offering larger food, with live shrimp still being the most easily accepted food. Mix in mysis shrimp or prepared foods whenever possible and scoop out any foods that they will not accept.
The fry will grow up to 1cm per month, slowly changing color over the first year. After this point they will begin to resemble their parents much more and can be released into a new tank. Do not release them with other gobies, especially other Engineer Gobies, as they will turn hostile.