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FAQs on Mormyrid Fishes Behavior

Related Articles: Mormyrids, Elephantfishes, Electrogenic Fishes,

Related FAQs: Mormyrids, Elephantfishes, Mormyrid Identification, Mormyrid Compatibility, Mormyrid Selection, Mormyrid Systems, Mormyrid Feeding, Mormyrid Disease, Mormyrid Reproduction, Bony Tongue Fishes, Electrogenic Fishes, Aba Aba Knifefish, African Butterflyfish, Arapaimas, Arowanas, Featherfin Knives, New World Knifefishes,

Elephantnose parasite treatment. Dis. and stkg f's       7/18/14
I have greatly enjoyed your website, and have in fact found it so
comprehensive, and helpful I have never had to write until now.
I have a school of small Peter's Elephantnose fish in a quarantine/holding 75g tank right now. In a couple days they will be moving to moving to their final home, a 160g (+ big sump) tank, which they will share with some Ropefish, Congo tetras, a pair of Pelmatochromis Ocellifer, and later possibly an African knifefish, some African Butterflyfish, and some other rarer West African cichlid and/or Ctenopoma species. (I probably will add the fish on second half of the list later, because for the next year or two
I'll be growing out a fire eel, an Astronotus crassipinnis (rare, smaller cousin of the Oscar), a Paratilipia polleni, and some Paretroplus maculatus
(hopefully) in the 160g before they move to the 300g tank. So that is for the vision for the tank int he next few years.)
I find Elephantnose fascinating, and that was my main motivation to design a tank around them, and to keep them in a group like in nature. I started out with nine, expecting that being a bit sensitive I might lose one, and I have had them for two months now. I had one die for no discernible reason not long after I bought them, but until a couple weeks ago, all the others were fine. They were all eating very well on live blackworms (rinsed  well), frozen bloodworms, frozen Mysis, frozen krill, and chopped earthworms.
During that first month most of them started to get nice and fat, and lose that thin look they come in with, however a few kept getting skinnier, even though they were eating well, and then eventually they stopped eating as well, and got even skinnier, and then ate less... etc., you get the picture. I am sure it is parasites, rather than competition for food, because there are not other fish with them yet (I wanted to get them
eating well before introducing them even to a sedate community tank) and also because one of the very skinny ones was one of the largest, most dominate of the ENs.
I hesitated to treat them all for parasites, because I know they are sensitive to many meds, and I didn't want to risk the ones who were healthy for the skinny ones. I eventually separated the two skinniest ones to try to treat, but by that time they were too far gone and I lost them. I want advice on what anti-parasitic to use on the six who are left, because I really want to treat them all, just to be on a the safe side. I have a couple still alive who aren't gaining weight like the others. It is very similar to the "wasting disease" wild caught loaches often come in with. I have available to use PraziPro, API General Cure (Prazi and Metronidazole) and Levamisole. What would you recommend?
<The combination of the Praziquantel and Metronidazole... either as a mixed product as you list from Aq. Pharm., or blended together yourself... delivered via foods>
Also a separate question, but do you think I should add a couple more Elephantnose once they are moved to the 160g? Six seems to me to be on the low side for a group of them.
<Six is fine... and what I would stick with. As having more adds to the possibility of the "last one" getting picked on, doing poorly>

Thank you so much, and sorry that it was a bit long!
*Ariel Johns*
<Cheers, Bob Fenner>
Re: Elephantnose parasite treatment      7/18/14

Thanks so much for the prompt reply!
Quick follow-up question: the API General Cure's instructions are for mixing in the water, so what would be a good amount to use mixed with the food?
<Mmm, IF you using the API in the water, realize almost NONE of it is going to get inside the fish/es (FW fish don't drink their environment... unlike marines). IN ORDER to treat for internal parasites... Let's just have you read on WWM re: http://wetwebmedia.com/FWSubWebIndex/fwmaintindex.htm
scroll down to Disease, read re the compounds involved here>
Each individual packet contains 250mg Metronidazole, and 75mg Praziquantel. Should I mix one packet with water (how much water?), and then soak their food in it? How long should I treat them with the medicated food?
Thanks again!
<Do the reading. BobF>

Dolphin Fish, Mormyrid     1/17/14
I want to start off by saying your forum has been quite helpful over some of my fish keeping experience. I'm always seeking knowledge on new fish species, diseases, and all of the above and always manage to come across your website; which always seems very wise. I have a mountain of questions for you, however I will try to make this as to the point as possible now.
<Real good>
Anyways, a little over a year ago I came across the Mormyrid, particularly the dolphin variety, and became infatuated.
<Neat animals; playful, intelligent>
 I tried to gain as much knowledge on them as possible and a few months later after being satisfied with  my preparation, I started searching for one. I looked over a year, came across a few iffy ones, but was eventually surprised by my boss with two little dolphins waiting for me at work (I work at a LFS.) I believe I ID'd them as Mormyrus Kannume or Caballus, but who really knows?
<Closest is likely Fishbase.org as a taxonomic/identification resource>
I believe I have a respectable amount of knowledge on these fish now, but was wondering if you could fill in the gaps for me, if possible. I was given 2 dolphin at around 2" at most, one clearly more dominant than the other. I took them both with plans to eventually either have them in separate tanks or at least "beef" up the weaker of the two with good care and a good diet so it was stronger for it's next home.
I've had them since the end of November and they are both still alive, the larger being closer to 4" (at least) and fat now, and the lesser being just slightly larger than before but the same weight except at feeding time when they both get big round bellies. They have both been extremely active and seem to be the happiest fish all the time. They're in such good spirits, they volunteered to go right in my net for me when I caught them while planting their tank for them. Very interesting fish indeed.
<Attracted to the metal likely>
My set up: 37 gallon tall (grow out tank)Trying my hand at a planted tank Substrate is 1/2 soft soil (Mr. Aqua Water Plant Soil)
 with gravel underneath (chose to reverse substrates and not cap for dolphins delicate noses) and the other 1/2 is fine natural colored sand.
Driftwood with java moss attached rock cave Hairgrass3 sword plants3 bundles of mixed plants1 moss ball
Temperature is kept on the warm side between 80-82F degrees50g sponge filter (though might be changing filtration soon) Additional airstone in sand
4 apple snail tank mates, 1 egg sac currently present at the surface. 3 Otocinclus (just added)1 Dwarf Gourami (just added)
Dolphin Diet (fed before bed time, but will eat any time of the day):Live black worms (cleaned nightly)
Frozen bloodworms
Frozen Daphnia
Will not touch: Any pellets (of course)Frozen brine shrimp
Water changes were weekly/bi weekly 25%-45%  but these guys seem to have an issue with either my tap or my dechlorinator (SeaChem prime) so against my nagging desire to be fastidious, I've lowered the water changes to when it's needed since the planted tank seems to take care of a lot on it's own.
<Best to store all make-up, change-out water for a week or more ahead of time of use>
I'm looking into getting an RO system at home to fix this dilemma for me so I can clean more often without worrying about irritating the fish.
I have added 3 Otocinclus (monitored for sucking on other fish) to clean the algae and 1 dwarf Gourami to get the bugs since apparently these things are more common in planted tanks. After reading about dwarf gouramis on your page though, I'm rethinking my pest control choice. I also starting dipping my plants in hydrogen peroxide before adding since I thought this was a better choice than bleach.
<Alum is even better... search the Net, books re its use here>
Water parameters currently:Temp: 82-83F, it's a bit warm here in California
<Not to worry. Periodic forays into the upper eighties F. are not a problem>
PH: 6.8 ishNitrite: 00ppmNitrate: 20ppmAmmonia: 00pmKH: 40ppmGH: 180ppm
My questions for you:*What other food options can I do for these fish?
<Anything "meaty" of size... e.g. Tubificids... frozen/defrosted better than live; may take some dried>
 And has their nutrition been met so far or do I need to add something else? *What is the average breathing rate of these fish? I've noticed since day 1 that they seem to breath extremely fast. Should I consider this their normal rate, or is this something I should have been paying attention to?
*Are there dechlorinators that are known to be better for these types of fish?
<Mmm, yes... the Kordon (NovAqua, Amquel) and SeaChem product lines are my choices>
I do not have the option of having my water sit for a week before adding it to the tank. Nor is it practical for me to have 20 gallons premixed and then added to the tank as I'm a 5'1 female and am battling chronic health issues. 
<Ahh, understood... and sorry for your health issues. The RO mixed will help tremendously here>
*Will these fish be ok if supplements are added correctly? i.e. adding SeaChem Flourish and/or excel? *Will adding pressurized C02 be ok if I had an indicator monitoring it?
<These additions; as you state, added properly, will be fine>
*I noticed the dolphins being a bit lazier, not swimming wildly (but happily) around the tank all the time. Is this due to comfort?
<Are fine; "happy" as you state, when out and about searching, curious re their world, interacting w/ each other>
The smaller hides when it can and usually only comes out when being chased or when it's dinner time, but the larger isn't as ruthless and chasing the smaller so often, so it's not showing itself as often. The larger one, and one I can see resting since it's too large to hide under things, is still active and noses through the soil quite often. It has bursts of energy or times of the day, but I see it resting on the bottom sometimes now. This might be normal for most fish to "nap" but I've not seen this much before now with them. It is possible they are growing more accustom to me and don't swim erratically when I come to watch them now, but I'm unsure if it could be something more serious. The larger dolphin used to tear at the smaller one's fins all the time, but now they're completely healed and intact. Is this mercy or a sign of more ominous issues occurring in the tank?
<Mormyrids often don't "get along" in the same, smaller volumes... will do so temporarily if crowded... You may find that the larger one will calm down if given a "shelter"... can be a tube of PVC, glass chimney or such (i.e. clear/transparent) or not. Otherwise; best to have these fish in two separate systems>
Attached are some photos.#1-week 1 of having them both#2-12/14 of larger dolphin#3-today, larger dolphin. excuse the water spots#4-today, larger dolphin#5-today, larger dolphin. Most important to show, I noticed some dark spots on the fins of this fish. There is no ammonia present, but I also just did a water change 2 days ago. The white specs seen are not on the actual fish but on glass (hence the Gourami, still getting used to the critters associated with more planted tanks) this is the "resting" I was speaking about.
Thank you for your time and patience reading through this, I wanted to be thorough as possible. I've got a 125g and a 240g as well and these are just my babies. It took so long to get them and I want to make sure they are cared for properly, though I'm a bit overbearing when it comes to these two. Looking forward to hearing from you.
Have a great night! Lauren Saunders
<Thank you for sharing. Bob Fenner>

Mormyrids... Stocking tog., beh. 2/7/12
If Mormyrids are crowded, does this bring out a different behavior that is sustainable and can they put up with the presence of many other Mormyrids in close proximity without being stressed by each others fields?
<Does seem to be the case in retailers' tanks'¦ but whether sustainable long-term at home, I cannot say. Would not recommend overcrowding any fish as sensitive as these.>
Does this video show there is a benefit to crowding them, and they are adapted to put up with large groups of their own kind, like with Tropheus?
<And even with Tropheus, there are huge problems with nitrate-sensitivity, filtration.>
The person who has that tank said that out of the Mormyrids he has Campylomormyrus tamandua is not very aggressive in groups, is that well known to be true?
<The species is not commonly kept, so it's hard to say. Baensch describes them as "peaceful loners" and comments that in groups bigger ones bully the smaller ones, preventing feeding. So your problem may be a long time in coming, with fish seemingly coexisting for weeks, months until the weaker ones starve.>
Also wonder what the guidelines are for petrocephalus, they are schooling and small so how much room and how big a school is needed to keep them. And they still need pvc pipes to hide from each other? Is a 3' tank too small for a school of petrocephalus, will they eventually breed and kill each other in that size tank?
<Would treat as any other medium-sized, delicate schooling fish, such as Glass Knifefish. Oversized tank, oversized filter relative to their size. Get the tank up and running for some months before introduction. Maintain with peaceful tankmates selected to play the role of dither fish (surface-swimming Rasboras or Danios for example) rather than anything midwater or benthic. A tank upwards of 55 gallons with a filter rated at not less than 8 times the volume per hour would seem prudent. As with all Mormyridae, the more caves, tubes, robust plants the better. Although gregarious, that doesn't mean this species "likes" its own kind -- just as with any schooling fish, even Danios, the stronger will be bullying the weaker, albeit rarely to the point of death. Rather than keeping 6, aim to keep 10 or 12.>
<Cheers, Neale.>
Re: Mormyrids 2/9/12

Why are Mormyrids so sensitive to chemicals and metals, in a way most other fish aren't?
<They just are. All fish are sensitive to copper and formalin and suchlike.
But some are more sensitive than others, and Mormyridae are at the very sensitive end, like Stingrays.>
I know they're stress prone and aren't treated properly usually, but the water issues, is their one trait that makes Mormyrids so frail in that way?
<Pretty much everything about them is demanding.>
The article on them on WetWebMedia says to treat tap water and let it stand for a weak, ideally. Is there a tap water test to tell you if your tap water is likely to kill them?
<Water chemistry actually doesn't matter much. So your issues are ensuring copper and ammonia are neutralised, as well as the usual chlorine and chloramine. Mormyridae aren't killed so much by bad water as bad water quality.>
It seems like there are many possible ways for that to happen, so I'm curious as to why.
<Just is. Cheers, Neale.>

Longnose elephant nose behaviour 9/13/10
Two months ago I purchased a Longnose elephant nose from the LFS I work at.
I was a customer there for a few months and I noticed that Longnose elephant noses (sold as Double-Trunk Elephant Noses) were much more skittish and sensitive than the common elephant nose.
<Possibly; none of the Mormyrids is an "easy" fish.>
The two LNEN that I saw hid all day, rarely came out of hiding for feedings and died after a month. When I started working there, there was one that I saw that I was debating getting. This one wasn't as nervous and even came out of hiding one day while I was looking in the tank. He did eat as much as he could (before other fish ate the food), but was very easily startled.
After maybe 3 weeks, I bought this one.
So now he is eating a bit more comfortably, but still easily startled. He actually comes out and swims around in a circle before retreating to his cave to let me know he is hungry. If I walk over to the tank to look at him, he hides though.
<Well, yes, does tend to be their nature. They're nocturnal fish, and any activity during the day only happens when they feel completely settled. One issue is that in large groups these Mormyrids are schooling fish, but once
kept singly they become much more nervous, like a single Neon tetra. The flip side is that within small groups, 2-5 specimens, bullying is very common, and the dominant specimen often kills the others, or at least, bosses them around.>
At work, when we get large common elephant noses they quickly learn to come up and eat right from the turkey baster (used to spot feed). Many trade-ins are the same way.
<Indeed. Gnathonemus petersii is a fairly aggressive, pushy species by Mormyrid standards, and I dare say that this is the reason why this species alone is regularly traded.>
So, finally what I would like to know is, are these elephant noses normally much shyer than common elephant noses?
<Apparently yours are. Campylomormyrus are not widely traded, so it's dangerous to make generalisations. But there may well be some behavioural differences that mean these species adapted less well to captivity than the
commonly traded Gnathonemus petersii.>
Also, how long does it normally take them to be comfortable enough not to hide as soon as they see you?
<Impossible to say. A lot will depend on the tank. In a large, shady aquarium in a quiet room and decorated with a soft substrate, floating plants, and a few surface-swimming dither fish, I'd expect yours to settle within a few weeks. But in a tank that's too small, in a noisy room, with a gravel or sharp sand substrate, boisterous tankmates, or unfiltered overhead light, it could take much longer, if it ever happens at all.>
Finally, I would like to confirm an ID. I believe that mine is a Campylomormyrus rhynchophorus based on what I seen on Fishbase and in Dr. Axelrod's Atlas of Aquarium Fishes. Only difference is mine seems to have a less deep body and larger eyes. I will attach a picture.
<Do please note for next time that we ask for images around 500 KB in size, whereas yours was 5 MB. Such big files quickly fill up our e-mail allowance, bouncing back other people's messages unread. In any case, your
specimen is certainly a Campylomormyrus of some sort, but there are several look-alike species such as Campylomormyrus cassaicus, Campylomormyrus elephas, Campylomormyrus rhynchophorus and Campylomormyrus tamandua it could very easily be. They're all much of a muchness, though adult size varies from 20-40 cm. Soft to moderately hard, slightly acidic to neutral water at about 24 C/75 F suits them well.>
Thank you very much for your time! Tyler
<Cheers, Neale.>
Reply to old answer, Mormyrid beh. 1/25/11

Hi, a while ago I was asking you guys for some tips on my extremely shy Campylomormyrus rhynchophorus.
<A very unusual Elephantnose fish'¦ a nice find!>
It's been a couple months, and he/she has become extremely comfortable in his/her aquarium and now is always out and will even eat out of my hand.
<Excellent. Yes, Elephantnoses can become very tame, and once tame, are easier to feed than when first purchased. They are supposedly among the most "brainy" fish and their behaviour in captivity is often remarkably trusting and playful.>
I bought a large Anubias sp. plant that fills the tank from corner to corner and have a layer of duckweed on the top and I feel the lack of wide and open spaces in the tank makes the fish feel more comfortable.
<I would agree 100%. While many aquarists see Duckweed as a pest, it can be hugely useful in tanks where the fish dislike bright light.>
This isn't a question, but just my experience with the fish and I hope it helps you guys out.
<Thanks very much for sending this along.>
And thanks for the great website! It is definitely one of my top sources when deciding on fish!
<Glad you enjoy the site, and thanks for the kind words. Cheers, Neale.>

Aggression in elephant nose fish 7/26/08 Hi! I just have a quick question. I was wondering if you could explain the difference between "playing" and aggression in elephant nose fish. <Gnathonemus will play with novel objects, like tinfoil balls; they fight with one another.> I understand they are more active at night, but we have one that won't leave another alone. <Aggression.> He even goes after the smaller fish in the tank. He is the newest addition, and Im actually starting to regret him. I don't want another at the first ones expense! <Gnathonemus petersi is a species that should be kept either singly or in big (6+) groups. What you're doing almost never works, and the weaker fish will eventually die.> Thank you in advance. <Sorry can't offer any more positive advice. This is a difficult species at the best of times, well known for intraspecific aggression, much of which involves bullying via electrical fields, so is invisible to us. Either separate the fish or add more, similar sized specimens. Cheers, Neale.>

Re: aggression in elephant nose fish 7/26/08 Thank you so much for your quick reply! I guess the next questions would have to be: I currently have a 50 gallon tank. Would it be safe add 2 and make it a group of 4? <Depends on how heavily stocked the tank is otherwise, and how big these Gnathonemus are. Adult size in aquaria seems to be around 20-25 cm, though potentially a bit bigger in the wild. I'm not convinced that 4 will fix the problem, but if you want to give it a whirl...> I think 6 would be way too much. <Not for this species. The problem is that they generate electric fields, and there is a optimum frequency that works best. The dominant fish will bully the other ones to force them to use less good frequencies. Moreover, simply being in the same tank is sort of like having the fish shouting at each other all the time -- tempers get frayed! In the wild they form big schools (dozens, if not hundreds, of specimens) but in aquaria this stable population structure doesn't occur.> And if I shouldn't add more, the only other tank we currently have going is a 25 gallon which is already home to a transparent knifefish. If I had to separate them would that be a suitable home for my new elephant nose or should I continue looking for a new home for him??? <I'm assuming the Glass Knifefish is Eigenmannia virescens -- another electric species! You'll get precisely the same problem with one bullying the other.> Once again thanks a million! Rachel <Hope this helps, Neale.>

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