Peacock eels include two species: Macrognathus siamensis, the peacock eel, greater peacock eel or spiny eel; and Macrognathus aculeatus, the lesser peacock eel, lesser spiny eel, peacock eel, porthole eel or spiny eel. These freshwater fish are members of the Mastacembelidae family and native to tropical Africa and Asia. Peacock eels in pet stores are almost exclusively adults.
Pour rinsed fine aquarium gravel or freshwater aquarium sand into the bottom of your aquarium to a depth of at least 4 inches. Peacock eels are burrowers who spend most of their time buried in substrate, only their heads exposed.
Fill the aquarium with treated water. Use a water conditioner that removes chlorine and chloramine and has a "slime coat." Position your submersible filter. You want the kind that affixes to the aquarium wall inside the tank, with outflow right at the water's surface. Do not use under-gravel filters or bio-wheels; they're too dangerous for this breed. Peacock eels are brackish water species, meaning they are freshwater fish that prefer small amounts of salt. You may need to add up to 1 teaspoon of aquarium salt per gallon of water to keep them happy and healthy.
Add aquarium plants. Peacock eels need fairly heavy plant cover. They will uproot plants, so floating ones are ideal. Anachris is an excellent choice: It's inexpensive and readily available, and it grows without roots in low light. Planted tanks do not require any aeration devices whatsoever.
Fit your screen lid over the top of the aquarium. Your peacock eel will come out at night to explore and test every possible escape route. Make sure there aren't any. Place the light fixture on top of the screen lid.
Cycle your tank. This means letting the filter run to establish biological filtration before adding animals. It's best to add eels after cycling for around two weeks. Provide normal daylight patterns for your plants by leaving the light on eight to 12 hours per day.
Perform a 30 percent water change weekly. Clean the substrate with the gravel vacuum. Refill the aquarium with conditioned water. Peacock eels like clear, very clean water.
Feed peacock eels daily until you're sure they're eating and are healthy, then you may drop feedings down to several times a week, depending on how well your feeder animals establish themselves in your aquarium. Peacock eels are nocturnal-feeding obligate carnivores: They need live food. The best foods are bloodworm, blackworm or tubifex -- all can burrow into substrate and establish a colony inside your aquarium. This is ideal. After water changes, filter the used water through your net and return any worms caught by the gravel vacuum to your tank. Peacock eels are readily bullied away from food by fast-moving, aggressive, diurnal tank mates. Eels in a community tank must be supervised to make sure they eat. Try feeding them after dark. Many can be trained to take food directly from your hand.
If the ambient temperature in your home is at least 72 degrees Fahrenheit, you do not need an aquarium heater. If it gets colder, you do. Eel tanks must stay under 80 degrees. Temperatures 80 or higher kill their live food and cause toxic blooms.
- Do not expect to see much of your peacock eels during the day. These shy guys prefer the nightlife. Peacock eels grow up to 13 inches long. You need 36 gallons for one peacock eel and an additional 20 gallons for each additional specimen. Peacock eels are relatively peaceful but carnivorous. They will eat any tank mates who fit in their mouths.
- Take information from pet stores with a grain of salt. While many products are available and may be "recommended," that doesn't mean they're good for your fish -- especially food. Peacock eels need live food, no matter what the person selling the fish tells you. It's extremely rare for one to accept dried or even frozen food. These big fish need to eat a lot. Don't risk their health experimenting with dubious products.
- Purchasing wild-caught animals is risky. They suffer adjustment and health problems that are rare in captive-born pets. Collection for the pet trade endangers and sometimes destroys wild populations. Please keep this in mind as you select your pets, and consider pressuring stores to carry only captive-bred animals. If there is enough demand, hobbyists will find a way to reliably breed these animals in captivity.
Angela Libal began writing professionally in 2005. She has published several books, specializing in zoology and animal husbandry. Libal holds a degree in behavioral science: animal science from Moorpark College, a Bachelor of Arts from Sarah Lawrence College and is a graduate student in cryptozoology.