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FAQs on Mastacembelid, Spiny Eel Reproduction

Related Articles: Spiny EelsThe truth about spiny eels; A closer look at these popular but problematic oddballs by Neale Monks, Husbandry of the Barred Spiny Eel, Macrognathus panacalus by Marco Lichtenberger, 

Related FAQs: Spiny Eels, Spiny Eel Identification, Spiny Eel Behavior, Spiny Eel Compatibility, Spiny Eel Selection, Spiny Eel Systems, Spiny Eel Feeding, Spiny Eel Disease,
By Species: Fire Eels, Peacock Eels, Tire Track Eels,

Re: & breeding spiny eels 6/22/07 Hi Bob, How are things? <Fine Sallie, thanks> I would be interested in reading your eels eels eels production. <I see... and fortuitously we/WWM have a chap helping use (Marco Lichtenberger) who is quite "up" on Mastacembelid husbandry> Meanwhile I purchased some small spiny eels called "yellow tail spiny eel". I never really expected them to breed, but I have 7 fry. What do you think their scientific name might be? They resemble the photo on your site called Macrognathus panculus. <<See http://www.wetwebmedia.com/ca/volume_4/V4I3/Spiny_Eels/Spiny%20Eels.htm for more pictures/text on M. pancalus. See http://www.fishbase.org/identification/specieslist.cfm?famcode=432&areacode=&spines=&fins= for further species.>> The adults are about 4 inches long. There were 2 males and one female <<Good ratio. It seems most spawnings occur when there are more males than females.>> , but after the spawning one male died because of an extruded eye. <<Sorry to hear that. Wounds of these eels do heal better in hard water or slightly brackish water.>> They usually stay under the sand, but the day before I think the spawning occurred I saw the female hanging out in the plants that slowly rotate around in the middle of the tank because the eels have uprooted them all!!!! <Neat> <<Possibly she was looking for a place to deposit the eggs. Planting plants in flower pots wrapped in mosquito nets helps to avoid uprooting.>> I cleaned the gravel in the tank one day and syphoned the bottom of debris into a bucket. <<Yes, after about a week of floating in the water column below the surface they start living in the substrate.>> This was just before memorial day. I poured off most of the water I removed from the tank. Several days later I saw fry eyes in the bottom among some of the syphoned gravel. Thinking the eyes belonged to some Danios I had in the tank I dumped some live baby brine shrimp. During the next few days the pink brine shrimp in their bellies revealed an elongated gut (too long for a Danio). As they have grown it became apparent that they are spiny eel fry. I assumed the eggs were in the gravel, but your reports suggest they may have been placed in the plants and I was just lucky to find them in the gravel. <<Eggs typically hatch after 3 days, 7 days later the fry are usually in the substrate. Maybe this helps to clarify the date of the spawning.>> They are now 1/4-1/2" long. They are in a 15 gallon tank with natural lighting, a Cory cat, a pleco, some Danios and tetras and a couple of shrimp. They are fed black worms and trout chow. <<If they eat that, it's fine, especially the black worms are part of their natural diet. Others things eaten by captive spiny eel fry are live bloodworms, Artemia, Cyclops, Daphnia and Tubifex.>> The water is soft and slightly acid and the temperature varies from 68-80 degrees F. I would appreciate your comments and advice. <<Congratulations! Thanks for sharing. Your report is very similar to the first report on spiny eel reproduction known to me (1955). If you want that report, I can e-mail the pdf to you. But it is in German. Sounds you did everything right. If they eat well, they will grow quite fast. Beware, that all spiny eels can be jumpers. Another source of trouble are narrow holes in rocks in which they can get stuck. Last but not least, any wounds of them heal much better in harder water, but since they naturally occur in a wide range of water types, you can leave them in slightly acid water as long as they are healthy. Feel free to e-mail on progress or further questions/suggestions. Good luck with raising your eels. Marco.>> Sallie <I am cc'ing Marco here... He knows far more re this group's husbandry than I. Cheers, Bob Fenner> <<Thanks for your trust, Bob.>> <Well-deserved mein freund. Cheers! BobF>

Re: Breeding spiny eels follow-up 06/22/07   6/24/07 German is spotty. Maybe Marco could extract informative parts if you sent it to him first. <No need to send it to me. The comments with one set of brackets in the former mail were by Bob, the ones with two sets by me (Marco). The author of the probably first breeding report, Schoenebeck, notes he observed spawning of one female and 3 males after watching courtship behaviour for several weeks. This author did not find eggs, but his tank was covered with lots of floating plants. After siphoning his tank be noticed 5 fry still left in the bucket used for water changes (sounds familiar). He put those into a small extra tank with no other fishes, 5 more fry survived in the tank of the parents (maybe there are some left in your tank, too?). They were mostly fed live Cyclops, the older ones ate all kinds of larvae of insects and small worms. The water he used was quite hard (18°dH).> Actually the fry are still eating baby brine shrimp. <Okay. You may want to vary this diet with other tiny types of live food.> The adults eat the worms and trout chow. They only eat at night. <Earthworms fed with tweezers are usually tempting enough to train them to be fed during day if you want that. Should need about 2 to 4 weeks of practice, sometimes less.> According to your time-line they were at the bottom of the bucket as soon as they hatched and then soon ate the baby brine shrimp. They are growing fast. I will try to get pictures. <Thats great. I hope your fry will do well. Marco.>

Tire track eels birthing   5/20/07 i have a 55 gallon tank with three tire tracks and 3 Bichir eels...i believe one of the tire tracks is giving birth. how do i know and what should i do???? thank u <Tyre-track spiny eels do not give birth; they lay eggs. If your spiny eels are swollen abnormally, then you may have a problem. People often (mistakenly) give them live feeder fish and these can (often do) introduce intestinal parasites. Minnows and goldfish also contain thiaminase and large amounts of fat, and used frequently cause damage to the internal organs, so again, here's another reason not to use feeder fish. Assuming you're using the correct diet for spiny eels, i.e., worms, insect larvae, frozen prawns, etc., then perhaps you are feeding them too much? One last thing: female spiny eels have distinctly deeper bodies than the males (so the females look more flattened from side to side than the males). Spiny eels basically don't breed in home aquaria, but you never know, you might be lucky! Look out for egg laying behaviour. Cheers, Neale. PS, your spell checker appears to be tragically broken. 32 words, 8 spelled incorrectly. Not good.>

My zigzag eels mated, babies? >I just received a call at the office from my wife and my 7 year old daughter, informing me that we have at least a couple of 1/2" long zigzags in the 90 community tank. Hopefully I can catch 1 or 2 before they get sucked into the filter or eaten by the local residents.   >>Fish you *didn't* know were in the system? >Any advice? Should I try and locate/relocate the nest if the rest of the eggs have not hatched? I don't see too much advice.   >>Boy, you're not kidding!  I'm having a devil of a time finding info, too. >If anyone is trying to breed these eels, here is the environment: 90 Gallon AGA 40W Daylight Tube Smooth small river rock type gravel Artificial plants, tall and short Several caves made from slate, as well as many other nooks and crannies. Light on from 6:30AM to 8:30PM PH 6.6 Temperature:  77F Hardness: I forget the number, but it is VERY low. (long island, NY soft, acidic water) Nitrites: 0 Ammonia:  0 Nitrates: < 5ppm Tank Location:  Den where 7 and 9 yr old kids fight and play Nintendo. :-) Besides the 2 zigzags (about 6"), the tank has: 1 Black Ghost Knife (6-7") 1 Fire Eel    9" 5 Congo Barbs 2" 4 Pearl Gouramis 3.5" 5 Red Serpae 1.25" 1 Fat 6" brown (turning yellow) Oranda (don't ask) 1 Male Golden Gourami >>This is a toughie, to get the little ones out (who have survived being eggs and larvae thus far) you'd probably have to tear apart the tank.  Truthfully, I think that if Mom and Dad have gotten down already, they're gonna go at it again.  I, personally, would wait and see.  Maybe provide some tubes long enough and thin enough that only *they* can get into, to help along their chances of survival.  Otherwise, I'd leave them be, unless you wish to remove Mom and Dad to their own breeding tank.  If you do that, this may upset their readiness to breed, but if you carefully recreate same conditions, and add the benefits of no food competition and start offering live foods (try to remember if you had done any large water changes, any changing tank parameters, etc. to help figure out what induced spawning) chances are you'll get lucky again with these fish. >Thanks for your help and keep up the great work! >>Quite welcome, and best of luck!  Marina

My zigzag eels mated, babies? >Hi Marina, >>Good morning, Bruce. Thank you for your advice. I only saw one of the little guys, less than an inch long and very wispy. About all I could find on their breeding is that they lay about 800-1000 eggs.  Based on the size, I would hazard to guess that maybe he was a month old. >>Well, my thoughts are these: first, if *any* of the larvae have survived those initial stages, that's a great sign.  One thing you don't want is to end up with a tank full of eels that you can't house or find homes for. >Looking back, I cannot think of anything out of the ordinary. I have an eclipse 25 with 2 blue diamonds and 20 or so Neons that get a 50% water change twice per week, so while I have the hose out, I give the 90 gallon a 25% change. Filtration is a pair of Eheim 2217's. I also have two air pumps, one on a wand, the other on a stone as I keep the tank pretty well sealed due to having eels. ;-) All of this is on a battery backup. As far as food goes, I feed flake (TetraColor) in the AM and late PM. After lights out, I feed Hikari frozen bloodworms (the only ones that they and the fire eel will eat) and beef heart. I will keep a log now of water stats, water changes, and feeding. >>It can only help.  And, if there's someone else out there with the eels breeding, or a breeder even, hopefully they'll pipe up and offer some more information.  In any event, I say if it ain't broke, don't fix it. >BTW, your site is great and I have found it a great resource. I am 44 now. When I was a kid I had a few  tanks. I got back into it when it was our turn to take home the kindergarten goldfish about 5 years ago. Went out and bought the eclipse, and then this February, the 90 AGA. My wife isn't a fish fan, but my kids (both with special needs) love it, so she will on occasion put some flake in! Once again, thank you for all of your help and advice. I will continue to be a daily visitor to your site. >>Very good to hear/know.  Glad the site is of such service, too.  Again, best of luck, Bruce.  Marina Trapping Spiny Eels Dear Crew, Would any of you have any experience in trapping eels? I have a 240gal. acrylic tank that I want transfer my Discus and Angels and Clown Loaches to.  In this tank are several Leleupi Cichlids, Dnobnoi and a large clan of Brichardi so I will have to take all the rock and wood out anyway. But, as you know, the eels will be able to go under the gravel.  The gravel is 4 to 5 inches deep and supports a jungle of Giant Val and a variety of other plants I would rather not have to rip up (their roots are a mass of tangles).  Also, there are LOTS of eels.  I had put just two in.  Now,  what are the odds that the 2 eels I bought were male and female!!!  Or are they able to change sex to fit the situation?  At first I was so amazed, and thrilled, to see the cutest little baby, but they just kept coming!  I think there must be at least 5 generations in there.  I think the smallest might be catchable because they don't seem able to get under the gravel and instead live amongst the plants and wood.  However Mom and Pop and several of the teenagers disappear with no trouble at all.  Any suggestions?  Thank you for any help you can offer. < WOW, WOW, WOW. If these are true Lake Tanganyikan eels this is the first incident I have heard of. African eels are very expensive and are not very common in the hobby. Too bad you want to swap them out. Many of these eels sell for up to $45 plus depending on the species and the size. I suspect that they have been breeding in the Val grass and feeding off the numerous baby cichlids being bred in the tank. A few years ago while diving in Lake Tanganyika my wife noticed a pair spawning with cichlids all around eating the eggs. Sorry they are a real pain to catch and I am unaware of any traps available.-Chuck

Fire Eels Hello-  I came across a website that had your email address and some information on the fire eel. A friend of mine recently purchased a fire eel and would like to get some more info. Would you happen to know how one goes about determining the sex?? <Not able to do... externally... as far as I'm aware> Also, is it ok to put more than one eel in your aquarium?? <Yes... a docile (though does get large) species toward fishes bigger than mouth-size, including other mastacembelids. Bob Fenner> She would really appreciate any info you could give on the subject.  Thank you, JB Hampton

Capitalization, Spiny "Eels" - 12/06/2005

Hi, my name is Silas. I <Your name, I, beginnings of sentences.... PLEASE capitalize....> have two peacock eels I got from a local PetSmart. Tonight I went to clean my tank and I noticed some little worm like things swimming around. I thought they were parasites but then I thought they could be baby spiny eels. <Highly unlikely that these are baby eels. Also, they are not necessarily parasites. Please search on WWM.... start here: http://www.wetwebmedia.com/FWSubWebIndex/fwinvertfaqs.htm .> I was wondering if they can have babies and how big they are. <I recommend a Google search on "breeding spiny eels" or "breeding peacock eels" for more information on the topic than we have available here.> I don't know what to do, so I e-mailed you. Please try to e-mail back soon. the "things" are really small and look like parasites so please tell me if they can be babies or if they are parasites. <Read, my friend; much to be learned here and elsewhere.... I suspect your worms are "visitors" of a sort, indicating an overabundance of "food"/nutrients in your tank. Wishing you well, -Sabrina>

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