Peacock eels are species of
Macrognathus, usually
Macrognathus siamensis. They're quite small fish (typically getting to about 20 cm under aquarium conditions) so while predatory, they're not particularly threatening to anything bigger than a male guppy. Unlike the larger spiny eels (genus
Mastacembelus) these smaller eels appear to be gregarious, and are best kept in groups of at least three specimens. They will be much more outgoing kept thus.
All the small spiny eels are sensitive to abrasion of the skin. Unless the eel is kept in a sandy aquarium, this is a very real risk. In fact, I'd class it as an almost dead certainty. What happens is the skin sooner or later gets scratched, the spiny eel develops a bloody patch across the wound, bacteria set in, and then the fish dies. Quite possibly Erythromycin or similar would help, but it's simply easier to keep them in tanks with smooth (not sharp!) silica sand rather than gravel. Obviously avoid things like Tahitian Moon Sand because that stuff is lethally sharp and even the manufacturers tell you not to use it with bottom dwelling fish.
Feeding is another big problem. These eels will eat wet frozen foods such as bloodworms as well as small live foods like earthworms. But they are too slow to compete with catfish and loaches, and I'd simply recommend against combining (small) spiny eels with ANY nocturnal bottom feeders.
Finally, they're great escape artists. If they don't starve and they don't die from bacterial infections, there's a good chance they'll end up on the carpet.
I wrote a piece for one of the fishkeeping magazines a while back, called "
The Truth About Spiny Eels" that your friend might find useful. Essentially the argument is that these *aren't* easy fish and despite being widely sold, most people don't have community tanks ideally suited to their very specific needs. On the flip side, these are smart, rewarding animals if you take the effort to care for them properly. The bigger species at least become hand tame, and actually rather friendly.
Cheers, Neale
