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FAQs about Shark Behavior

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Related FAQs: Shark Systems 1, Shark Systems 1, Sharks in General, Shark Identification, Shark Compatibility, Selection, Feeding, Diseases, Shark, Ray Eggs, Coldwater Sharks, Leopard Sharks, Heterodontus, Blacktip Reef Sharks, Nurse Sharks, Moving Sharks


Sharks and Rays in Aquariums
Gaining an understanding of how to keep these fishes in captive saltwater systems   

New Print and eBook on Amazon

by Robert (Bob) Fenner

Shark attack kills German tourist at resort in Egypt   12/6/10
> Hi Bob,
> http://www.bbc.co.uk/news/world-middle-east-11922032
> "Shark experts and local observers have offered a number of possible explanations for the attacks. Some say overfishing in the Red Sea may have driven sharks closer to shore. Meanwhile, some said predatory sharks could have been drawn to the area after a ship carrying Australian sheep and cattle for sacrifice during last month's Muslim festival of Eid al-Adha dumped the carcasses of animals which had died dying during the voyage."
> Cheers, Neale
Yikes indeed. B

Question on fish size 3/25/2009
Hi WWM Crew,
I have a question(maybe a silly one);on the info you have on fish species you mention amongst other things size at mature, my question is: if surgeons, angels and other fishes size in captivity is usually half that on the wild, does it applies the same criteria regarding sharks, or they reach the same size in captivity than in the wild?
<The "half" size measure is about right for sharks, rays in captivity vs. the wild as well>
Thanks for your time and for this incredibly informative site.
Saludos desde la Ciudad de México.
<Oh! Buceamos en Cozumel, Quintano Roo ahora. Roberto Fenner>

Question on relationship between remora and sharks  8/24/08 Hello My name is Jey and I'm in 7 th grade. We are studying symbiosis. When I was searching through internet I found that the remora eats the sharks "leftovers" but that the remora does nothing for the shark. But I was told that the remora helps the shark . I would like to know if you can help me find in what way it helps the sharks because practically in all the sites I've read it says that the sharks receives nothing from the remora. Thank you Jey Rivera (Puerto Rico) <I speculate that sharks do receive a modicum of benefit from symbiotic Echeneids... the attachment and moving about with their modified dorsal fin likely is useful in dislodging external parasites... and a further "guess" is that the Remoras may act as "look outs" for both food items for the shark, and alert them to the presence of predators. Bob Fenner>

Shark Question, beh.... env. dis.   8/3/07 Hi (yes, again!!!), This is a question on shark behavior, and I'll give you the quick background, though you are probably all too familiar with me. The tank is a 200 gallon, with approximately 100lbs of live rock, sand substrate 2 to 3" deep, filtered by a Fluval FX5 with bio media only and filter pads (cleaned at worst every two weeks), a Magnum Canister hang on for water flow and carbon, a Penn Plax 300 power filter for mechanical, extra carbon and bio filtration, and a large protein skimmer rated for 200 gallon tanks (hang on variety). 0 ppm on both ammonia and nitrites, <10 nitrates. PH is at 8.2. Salinity is at 1.022 right now. <...> The occupants are a banded cat shark at 8", a passer angel at 5", a yellow tang at 4" and a dogface puffer at 5" (oh, and the cleaner wrasse, yes the original cleaner wrasse that I was fussed at for buying by you guys weeks ago, point well taken and won't occur again). We have just completed the ich treatment of quinine sulfate, at which time I did a 25% water change and began running carbon again to remove it. The passer developed Lymphocystis (sp), I'm assuming from the treatment of quinine and the extra duration of no water change during that period. The shark, prior to treatment, acted wonderfully, eating well, usually a cube of shark formula soaked in Zoe, cut into pieces. During the quinine treatment, he did not have much of an appetite, though this may have been due to water quality during the treatment. Now, conditions have returned to above stated. The shark, during the day, spends his time in a cave under the rock, which he has always done. In the evening, he comes out when I feed the other fish, but his behavior is odd. He actively swims up and down the tank glass, often time pushing his head above the water. He eats ok, but not with the aggression he used to have. He will take a piece of the formula and eat it, then rest on the tank floor, then resume this frantic swimming. He will usually eat two pieces or so, then he will mouth the third but not eat it. After, say, ten minutes, we will go through the process again, and he will consume two more, mouth the third, etc. I'm more concerned with this erratic swimming behavior, as it seems frantic at times. It only occurs in the evenings after I've placed the food for the other fish in the tank. This has been going on for about a week now, I suppose. Monday I purchased about two dozen ghost shrimp and put them in the tank after rinsing them with fresh water. I've been doing this ever since the shark has hatched. They get consumed by something over the course of a couple of days, I'm thinking by the shark at night, as the puffer has a hard time catching them in the daytime. I only mention this because when I put them in, the shark came out and was slowly cruising around trying to eat them, and at that time his behavior seems normal. So, to summarize, he sleeps normal during the day, swims frantically up and down the tank walls in the evening when he seems hungry, but seems to eat less shark formula and in smaller pieces, like it's harder to mouth them. If you can make any guesses or have any thoughts, I'd love to hear them. Sincerely, Thomas Roach <Likely the treatment and disease condition, coupled with the present too-low spg and likely nitrogenous material is mal-affecting the shark's appetite/behavior... Correct this animal's world and hopefully its behavior will improve. RMF>

Marbled Cat Shark - 10/13/06 Hi my name is Jonathan, <<Hello Jonathan>> I was doing some research about these sharks because mine has been acting up.  I've had it for a couple of days, I've been keeping up with the feeding etc...I've been feeding it human consumable shrimps. <<Will need a more varied diet...squid, marine fish flesh, etc.  Along with vitamin supplementation>> It even ate a couple of our small fishes in my tank. <<Yes...a very predatory species>> The tank is a 55 gallon tank 4'x2'x2'. <<Much, much too small...a couple hundred gallons needed here...in the least>> We just got it but we will upgrade soon. <<Make it quick>> I take it these are bottom dwellers however this shark has been swimming around a lot. <<May be an environmental issue>> It is a rectangle tank and I fear it scratching against the corners when it swims around. <<A possibility in this "too small" environment>> This shark looks well about 1' long and the previous owner says he had it for a couple of years.  Any suggestions? <<Get this animal in to a suitably large and equipped system...and start reading here (http://www.wetwebmedia.com/sharksystems.htm) and continue reading among the associated links in blue at the top of the page>> Thanks in advance. <<Regards, EricR>>

Re: Sharks......Again - 09/24/06 Sorry to keep bothering you, Eric, but I have one more question for you and that will be it for a while, I promise! <<No problem Chad>> On Fishbase.org, how do I tell how much a certain species grows per year?  I know how to get to the "Growth" section but I can't tell what is what!  Need help....bad! <<Hmm...this particular data looks to not be available in most cases.  You can try clicking on "Search for more references on growth:" and chasing the resulting links around.  You could also try to find/contact a public aquarium housing the species in question and see what their experience has been re growth rates>> Thanks, Chad <<Regards, EricR>> Believe me, I will!!!!!!!!! Seeya Eric! Many thanks, Chad <<Cheers mate!  EricR>>

Re: Which Shark(s) for a 1,200 Gallon System? - 09/12/06 Just one final question. How much does a Brown-banded Bamboo Shark swim around at night?  Just as much as an active shark would during the day maybe? <<Hmm, don't rightly know...would think much of their "hunting" would be done at night.  Take a look here (http://whozoo.org/Anlife2001/callmatt/CMM_Bandedcatshark2_JES.html) for some more info on these sharks>> Hope I didn't take up too much of your time, I know you're busy with all of the questions that you guys....and girls receive! <<Mmm, and even more so when the 'Bobster' is away.  But no worries my friend...is what we do>> Thank you very, very much, Chad <<You're very much welcome.  EricR>>

Strange (Shark) Discharge   4/7/06 Hi, Bob.  I have a 2-year old female Brownbanded bamboo shark I raised from an egg.  She is about 26 inches long which I understand is close to sexual maturity. <Yes>   Her diet is mostly a mix of shrimp and squid (both injected with liquid vitamins) which I sometimes supplement with live night crawlers.  It's my impression her health is excellent.  Recently, every couple of weeks in the middle of the night when she is active, she has been discharging 'packages'.  These things are brown and the size and shape of a peanut.  They have a skin like a grape and will pop when I apply pressure to them after I pick them up out of the water.  They are filled with a brown gunk.  Any idea what these might be?      Dean C. <Likely early attempts at reproduction... "takes two to tango"... Bob Fenner>

How Quick Does a Tank Buster Become a Tank Buster? - Bamboo Shark  12/24/05 I wanted to know if you guys know how many inches a bamboo catshark will grow each year. <I'm going to assume bamboo catshark refers to the animal known as Chiloscyllium punctatum...how I detest common names at times. On to the subject at hand: Well it depends on the feeding habits and metabolism of the individual. Furthermore the growth pattern is not simply "X"-per-year" but rather more along the lines of a negative slope. As in the animals grows quite quickly when young and then slows as it grows. In my experience they usually attain 18" quite quickly after birth (within a year).  Then the growth slows to a few per inches of year though growth is still quite noticeable. Once they hit the 30" mark then growth slows considerably until reaching the adult length a possible; 42."> Thanks. <Welcome, Adam J.>

Nurse shark spitting water out of the tank  12/21/05 Ok here isn't something I have seen before but the shark is doing it most nights. Once it become night and he becomes active, he will swim along the top of the tank. He will then go up to the top of the tank and spit water. There is one section that is not covered and he send the water flying out. any reason for this particular behavior? <First off Peter, no home aquarium is large enough to keep a nurse shark in conditions to its liking.  Why do pet shops sell these, they need to be banned.  Are you aware these sharks attain lengths of 16 feet?  They will NOT adapt to aquarium conditions and don't listen to anyone who tells you their growth can be controlled by smaller feedings or by the size of tank they are in.  His behavior is largely due to the negative conditions he is living in. Stress, my friend. It won't be too long before he will be attempting to jump out.  I'd try to find a home for him such as a public aquarium.  Sharks are best left in the sea where they will do the most good.  James (Salty Dog)>

Shark acoustic characteristics 7/12/05 Do sharks broadcast any type of acoustic signals? <Mmm, yes... low frequency, low amplitude "body noise"> I know that they can hear quite well but a question has come up as to whether they emit sounds for communication or characterization of their environment like the toothed whales do. Thanks, Thomas L. Parker <I would/am guess/ing... that this sensory input does play a role in communicating at short distances. Bob Fenner>
Re: Shark acoustic characteristics 7/12/05
Thanks, Bob. I just stumbled across the web site. I was doing some research on shark characteristics that might be detectable in time to get people out of the water before the shark has time to strike. <Am sure you've seen the Australian electrical "pod" product of this last few years... really works> Right now, it looks like detection might be limited to visual from above but that is predicated upon light conditions, depth of the water, water clarity and the characteristics of the bottom. <Mmm, I suspect smell, electrical, vision, and low pressure sense in this order are the typical sensations of detection> So the next thing is to find out how fast the individual moves when just cruising or in hunting because that will let me calculate the coverage time limits to place on the developed system. Essentially, how often do I need to survey a particular area in order to detect shark entry / presence. <There is such data for a few species of sharks... Do you belong to the Elasmobranch group of the ASIH?> I read with great interest the stories of people trying to keep sharks in captivity. It really makes me appreciate what the commercial aquariums have to go through to have a good exhibit. I had no idea how delicate sharks really are! <Indeed they are> Top that off with the fact that I thought that the red tailed sharks in the pet store were just a variety of tropical fish - I did not know that they were a species of shark. I kept to guppies and mollies when doing the aquarium thing - my room was more like a pond! <Freshwater minnows, Cyprinids> Once again, thanks for the information, Tom Parker <Glad to share, speculate. Bob Fenner>

Bamboo Cat shark Question 7/6/05 I read through all the forums, that took some time!! But I have a question about a behavour that my cat shark is doing. I have about 2 inches of fine sand in my 125gal tank and there are a lot of live stuff seen in the sand. My shark actually pushes his noses and mouth into the sand and shakes around and then he will come up and I can see the sand sifting through his gills and then back in the sand he goes. Is he eating all the live critters in the sand?? <Is likely looking for food organisms> He also eats squid and krill with no problems. I didn't know until today that they need vitamins too. <Yes... as do you and I... from foods, exogenously if not> I will purchase vitamin first thing and start offering them to him. If I were to do the vitamins and his other tank mates eat them will it be ok?? <Yes> It's hard to get the food to him, sometimes. The grouper and lionfish eat the squid as soon as it hits the water. Once they are full then I can stick feed him. But sometimes they get that food too. I just need to know if this act he's doing is safe. Thanks a lot!! Stephanie <Thank you for sharing. Bob Fenner>

Shark jump How prone to jumping are bamboo sharks? <Very> Mine jumped yesterday, I found him next to the tank. Fortunately, he seems ok. Ate well the following day. My water conditions seem fine, any idea why he jumped? <Too small a system, something "spooked it", because it can...> He is 3 feet long and I feed him 4 or 5 chunks of seafood about 1 inch square. He would eat more, is feeding more a good idea? (I am feeding 3 times a week now) Thanks, Tim <Feeding more is a poor idea... better to keep small/er, hungry... will live longer, better life. Bob Fenner>

- Pacing Port Jackson - I purchased a port Jackson shark from my LFS yesterday and he is swimming up and down the sides of the tank pocking his nose out of the water, He lives in a 280 oceanic with skimmer wet dry and a canister filter. Water is 77f ammonia 0 nitrite 0 nitrate 0 ph 8.2 sg 124 what would cause the shark to do this he just goes up and down until he gets tired then sits on the bottom please help. <This is a cool water shark, and you're keeping it at tropical temperatures. You need to invest in a chiller now or prepare to lose this animal. More reading for you here: http://www.wetwebmedia.com/coolh20sharks.htm > Thanks
<Cheers, J -- >

Sharks and Rays in Aquariums
Gaining an understanding of how to keep these fishes in captive saltwater systems   

New Print and eBook on Amazon

by Robert (Bob) Fenner
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