Five more minutes please: Sleeper Gobies (Family Eleotridae)
Mellow predators, Sleeper Gobies often seem like they prefer lazing about to hunting (hence their “Sleeper” moniker). They are interesting fish which can make lovely tank inhabitants, assuming of course you don’t keep them with much smaller fish. They may not be the most active, but they will win out eventually!
Species
Eleotridae is one of the nine Families under the Suborder Goioidei, which also includes Gobies (Family Gobiidae). Eleotridae contains 182 species over 35 genera, of which 8 are native to the continental United States:
- Dormitator latifrons (Pacific fat Sleeper)
- Dormitator maculatus (Striped Sleeper) [pictured]
- Eleotris amblyopsis (Large-Scaled Spinycheek Sleeper)
- Eleotris picta (Spotted Sleeper)
- Eleotris pisonis (Spinycheek Sleeper)
- Erotelis smaragdus (Emerald Sleeper)
- Gobiomorus dormitor (Bigmouth Sleeper)
- Guavina guavina (Guavina)
Of these species, the Striped Sleeper is probably the most commonly sold in fish stores. A few other species do find their way into the trade from time to time, including the Spotted Sleeper.
Conservation Status
The Pacific Fat Sleeper and the Spotted Sleeper are both considered stable and of Least Concern by the IUCN. The Sandwich Island Sleeper was determined to be Data Deficient and all other species have not been evaluated.
Distribution
Only one species, the Pacific Fat Sleeper, is found on the West Coast of the US, and only in Palos Verdes, California. It is also found in the Gulf of California and along the coast of Mexico, though. All the other species are found on the eastern coast of the US.
Description
Sleeper Goby size varies based on species. The largest, the Striped Sleeper and the Bigmouth Sleeper, both reach about 2 feet (though most Striped Sleepers average 12 inches) and the smallest, the Large-Scaled Spinycheek Sleeper, only reaches 3 inches. The other species are typically around 11-15 inches in length.
Sleeper Gobies are not terribly active fish and are generally happy loafing
about unless feeding or hunting smaller fish. They can be
territorial with their own kind, though they are pretty easily kept with other species of fish around the same size. Much smaller fish (such as the Poeciliid livebearers) are too likely to be eaten. Also, avoid keeping them with very aggressive fish such as Snappers or nippy fish like Puffers because Sleepers are slow moving targets.
They spend much of the day loafing about and sand or rounded gravel is likely appreciated. They may also lurk behind ornaments and in caves. Besides this hunting behavior, they are less shy and more “open” than most Gobies.
Feeding
Sleeper Gobies are predators and need meaty foods to stay healthy. They should accept frozen food fairly quickly, with a mix of squid, mussels, cockles, krill, filets of salt water fish, and other such foods being a good variety. Live invertebrates like earthworms and feeder shrimps are fine occasionally as well. Sleeper Gobies may eventually accept dried foods, especially high quality pellets like Spectrum.
Water Quality
Being brackish fish, these Sleeper Gobies need hard, alkaline water for long term health. Values upwards of 15 dH hardness and pH 7.5 are perfect. Most species of native Sleeper Gobies are tropical and require temperatures around 74-80 F. The Pacific Fat Sleeper is subtropical and does best in unheated aquariums, from about 65-68 F.
Brackish Suitability
The Family Eleotridae is well known for containing many species which are Brackish-tolerant fish. While Eleotridae in general tends more towards Freshwater with a tolerance for salt, most of the species native to the US are Marine fish that sometimes travel into brackish (and freshwater) systems. For these fish, keeping anywhere between 1.010 and 1.025 should be fine for long term keeping.
The exception is the Spotted Sleeper, which is not found in fully marine water. I fact, it really only inhabits low end brackish conditions. Likely around 1.003 is enough salinity.
Tank Size
For the largest species of Sleepers (Striped Sleeper and the Bigmouth Sleeper), you may need a tank upwards of 150 gallons if they start approaching maximum size. For the species that get to about a foot long, then 75-100 gallons would make a reasonable community tank. The relatively small Large-Scaled Spinycheek Sleeper would be fine in a 20 gallon “long” tank.
Breeding
Sleeper Gobies have been bred in the home aquarium. In the case of the Striped Sleeper, the male and female clear an egg-laying site, typically a rock or another solid object, and attach eggs to it. At 76 F, the eggs hatched in about 24 hours. At this point, the adults should be removed as the parental care stops after hatching. The young should be fed infusoria and other such tiny foods.
Final Thoughts
Though not active, and not exactly the most community friendly fish, Sleeper Gobies are still lovely additions to the native marine community. Yes, they are better kept in brackish conditions, but there are very few brackish native fish that can tolerate half strength sea water and are big enough not to be eaten.
Sources
Fish Identification, Fishbase
Eleotris Picta, Tropical Fish Forums
Sleeper Gobies (family Eleotridae), Neale Monks
Dormitator maculatus, The Aquarium Wiki
FAQs on Fresh/Brackish/Marine Sleeper Gobies, Wetwebmedia
Dormitator maculatus, Aqua World
FAQs on Fresh/Brackish/Marine Sleeper Gobies, Wetwebmedia
Our Native Fishes, John R. Quinn
