Anguilla marmorata

[Umbra]

This is my second round with these guys, bought some a couple years ago and they all died within a couple days of each other after a heavy feeding of frozen bloodworms - I'm guessing constipation since they all died with noticeably full bellies.

This batch came from the same place (Taiwan) at the same size (~2.5 inches) and are doing well. Just like last time they came semi transparent, mid transition from glass eel to elver and are starting to darken. The larger specimens now have almost no transparency left.

They're very intelligent and inquisitive, took only a few days to learn tong/hand feeding and are very responsive to any movement in the tank or the room. If I walk by the tank their little heads poke out from the crevices in the wood. I can't wait for these guys to grow, eventually I want to have them in an indoor pond with some koi. Not the fastest growing fish especially past the 18"-2' mark so I'm still plenty of years out before they hit true tankbuster status.

They're incredibly aggressive feeders, very greedy and nippy when hungry. Similar to when I kept a group of Gymnothorax polyuranodon, they sometimes nip each other while feeding and as a result it's not uncommon to see some very light abrasions - these usually disappear after a day or two. Right now I've been feeding them fine slivers of nightcrawler supplemented with some omega enriched brine shrimp and Okanagan mysis. Crawlers are the favourite by far and definitely get the strongest feeding response.

Here's a quick video of the little noodles feeding

 

[Umbra]

Here's a small updated feeding video of these guys. Despite what the video shows they can actually quite be picky with some of them turning their noses up at various other offerings including tiger/brine/mysis shrimp, silversides, tilapia etc. Chopped nightcrawlers seem to be the only universally popular food with this group so that makes up the bulk of their diet. It'll be interesting to see if their tastes change as they get older and I'm able to introduce other food items more easily. Adult eels are fierce predators and will take pretty much anything they can overpower including fish, frogs, small mammals and birds. They're known to quietly slink along the shorelines of jungle streams in order to snatch small animals coming to the shore for a drink, grabbing prey as they lean in to drink. Prey is either swallowed whole or torn into bite sized chunks via death rolling like a crocodile.

Growth rate at this size is still on the quicker side, with the largest specimens having grown from about 3-4" within the past 5 weeks. More than anything they have been putting on some mass and pigmentation as is typical when they transition from glass eels to elvers. Growth should slow down as they get larger and I'll be making some changes to their feeding schedule as they grow, reducing the frequency as they continue to get larger. As you can see there are a few runt specimens that can't keep up with the growth rate of the others so I'll be moving the larger specimens to a bigger grow out by Sunday while the runts will remain in this tank until they're large enough to join the others.

They are now completely fearless of me, actively out and about while I do tank maintenance and will swim between my fingers and nose around for food when I'm cleaning algae off the glass. They are always interested in any instrument I have in my hand whether it's a pair of tweezers or an algae scrubber.

 

[Umbra]

Monthly update time! Eels are growing, smallest specimen has been separated from the rest and is doing well in a small community tank, can hopefully reintroduce with the rest if the growth rate picks up.

The rest of the eels are growing with the largest closing in on 5". Those big specimens are slowing down on length and starting to put on mass, they are really looking like miniature versions of adult yellow phase eels. Pigmentation is starting to show faintly, likely will be more noticeable by the time they hit 7-8". Hopefully within another month or two they can be moved to a larger community tank to properly grow out.

In addition to minced earthworm and frozen mysis they are also eating prepared foods. The favourite seems to be NorthFin Bug Pro crisps which get almost as strong of a feeding response as earthworm. I will post an update photo/video soon.