An Underwater Peacock (Eel)
Regardless of what you call it, whether it's Striped Peacock Eel, Siamese Spiny Eel, Peacock Spiny Eel, Spot-Finned Spiny Eel, or just the Peacock Eel (because all of these names are actually Macrognathus siamensis), it still isn't actually an eel. Some older aquarium books will list a couple other species names for Peacock Eels, but these have been rejected. True eels don't have spines in their fins, and thus a spiny eel... isn't one. That being said, the look like eels, they act like eels and if you're going to keep a freshwater eel there are lots of good choice and among those good choices, the Peacock Eel is (probably) the best choice.
Peacock Eels max out between eight and ten inches long, with the record being just a smidge over a foot. They have somewhat more muted colors than a lot of the other spiny eels, being mostly tan with a thin lighter colored stripe running the length of the fish. Some specimens will have faint reddish or orange tints to their tails and all of them will have six cool tail spots as they mature.
None of the commonly available spiny Eels need brackish water; they all live and breed in freshwater and the Peacock Eel is no exception. Peacock Eels do like water that is on the soft end of the spectrum and slightly acidic (pH 6.5 to 7 or so). Normal tropical temperatures should be your goal, think 72-80 Fahrenheit.
A single juvenile specimen could be kept in a tank as small as 30 gallons, but we suggest going for a 40 breeder or larger, which would also be an adequate size for a few adults. They do not need a lot of depth in an aquarium so whatever you choose, opt for larger footprints over larger volume. Make sure this aquarium has a tight cover, without gaps. We can't emphasize this point enough. Even the tiny sliver of space around your filtration pipes will be enough for them to escape from, if you do not prevent this, they will exit stage left, and they will not live through the exodus.
Peacock Eels are burrowers, and as such you should always keep them in an aquarium that has a soft sandy substrate. This will protect them from scratching themselves up which can end in bacterial infections, one of two primary challenges in keeping spiny eels. You don't need much sand, an inch and half or two will be plenty even when they are adults. All the fish in this genus love to burrow and will have no problem turning this sand over regularly. As a result, there is little risk of these sand beds ever becoming anaerobic.
Plants are great when keeping Peacock eels. The obvious flaw with this plan is that the eels love to dig, and so rooted plants are a waste of time. Stick to floating plants and plants that can be attached to wood and rock like Anubias, Mosses and Java Fern. Make sure anything you use for décor is smooth sided as protecting the eels from themselves is the best way to keep them healthy.
While Peacock Eels are some of the best eaters in the family, spiny eels in general are sometimes tricky to get started eating in captivity, the second primary challenge. They are shy and generally nocturnal and so at least initially, they will likely need to be fed some live food at night. They are opportunistic carnivores and will relish ghost shrimp, feeder guppies, bloodworms and similar foods. Earthworms are a natural food for them that they respond well to, are easy to buy and dose and generally fun for aquarists to feed. In time, you can train your spiny eels to eat during the day and to take thawed foods. Keeping multiple eels together will help them acclimate more quickly and make them bolder in your aquarium. We recommend this; if you have a big enough aquarium, try at least three of them. If you are going to mix your eels with other fish, make sure those fish are also slow eaters, or add them to the display after the Peacock Eels have grown accustomed to captive feeding.
In general, spiny eels are rarely bred in captivity and this makes for an excellent challenge for the advanced home aquarist. For those you interested in keeping multiples, this opportunity is open. They are hard to sex even as adults, though females will be “thicker” than their male counterparts. Successful attempts at breeding other Macrognathus species in the past has been triggered by heavy feeding and large regular water changes. Sticky eggs will be deposited on just about anything plant based. They are fairly large (over 1mm) and take a few days to hatch. Baby Peacock eels will need some tiny foods like cyclops nauplii etc. and this will be a primary challenge for you.
If you are looking for a very unique addition to your aquarium and have a suitable home, a few Peacock Eels would make one heck of a cool display. They stay small and can be kept in groups. They eat well once established and are tolerant of other fish (at least ones that are too big to eat). This small size and peaceful temperament are among the primary reasons they are often recommended as a first spiny eel for new keepers. They are among the most suitable of the spiny eels for captivity and offer a rewarding challenge for hobbyists of all levels. Just take some time to get them acclimated to feeding, keep a tight lid and soft substrate at you're on your way to success! Head over to your LFS and ask them about getting you some Peacock Eels from Aquatropic today!