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

Re: Heterodontus Japonicus... shark sys. period  8/1/09
Thanks for the quick reply. I was wondering if I could use black sand for the system since I have heard it can stick to magnets I thought it may be a bad idea because of the sharks.
<... you do want to completely avoid ferrous materials in, about the system. And most "dark sands" lack much soluble biomineral and alkaline content, surface area for nitrifying, denitrifying microbes... which will have to be made up for some other way.>
Not sure if they are magnetic or even if the brand Im choosing is but Will research it thoroughly. Just wondering on your opinion. The tank has 2 Tunze wave boxes and I was wondering if I should remove these or not.
<You will want, need much more vigorous circulation than these can provide. Best with such large systems, animals to remote all pumping, valving mechanisms outside the tank... as in so-called "Closed-Loop" recirculation set-ups... To avoid metal contamination, preserve gear from not being broken, diminish the contribution of waste heat...>
Have also heard they are bad for shark tanks but the tank was set up with sharks before and the wave boxes. Just a bit confused and doing m research since I will change whatever I have to for the pair of sharks I plan. I have about 3 to 6 months of more planning so o rush, just research. Any help?
Andre
<You tell me. Bob Fenner>

Flow rate in Elasmobranch display; sump and refugia  3/5/07 Hey crew, <Hello.> I'm setting up a 180 gallon (temporary) shark tank <Key word being temporary.> and have a question regarding circulation. <Okay.. I have a 100 gallon sump (Rubbermaid tank) which is filled with about 60-75 gallons of water, and a mix of live rock and bio balls as media.  I also have a 55 gallon refugium and big skimmer(1500 gallon an hour) plumbed in.  I figured I would circulate the tank through the sump about 5 x an hour, does that sound right? <Yes, slightly more wouldn't be a problem but this is fine, provided there are other water-movement devices adjoining the display.> I'll also have powerheads going inside the tank for added water movement. <Mmm...as clumsy and as sensitive as sharks can be I would prefer closed loop manifold systems if you can cut it.>   What do you feel is right for the circulation through the refugium? <Depends, what is the targeted livestock (assuming it's a species of macroalgae here) in it.> I appreciate your advice. <Of course.> Thanks <Adam J.>

Re: Coral Catsharks... electrical, ray comp.    5/4/06 Hi again. This is the last time i will bother you I swear. <Heee! Be careful what you promise...> I was just wondering if a grounding probe would be a good idea for a shark tank. <Mmm, no... as stated, this is more likely to induce electrical potential than solve such issues in an otherwise properly equipped, set-up system> As I stated before I have 3 pumps and a heater along with the lights and the 2 Emperor filters. <These are hopefully grounded, wired through GFI's> I have read that these things can cause some electric current in the water and this will of course disturb the sharks senses. <Would if not...> I'm not sure if there is any current in the tank, and not sure how to test for it. <... then study> From my understanding the grounding probe will take away all the electric current in the tank they may be harmful to the sharks. I just want to make my aquarium as pleasing as possible for my sharks so they have a long life and hopefully breed. In your opinion what is the best food to feed them? <Isn't this how we started? This is posted (to the extent of my knowledge at least) on WWM> How often should I feed these particular sharks and how much? Thank you so much for the replies. You have helped me out tremendously with your responses. I do believe this will be the last help I need. <No...> Oh one last thing, if my goal is to breed these sharks, should I have them in the tank be themselves. Would it be possible to put a yellow stingray in the tank with them, and still have the sharks breed. Thank you. <This system is not large enough for a jamaicensis... Bob Fenner>

Re: Epaulette sharks/Pink Bellies/New tank on the way, sys. Pump sel.   8/23/06 Bob,   I have read though the linked page and now I am more confused than before.     <Let's see if we can clear this up>   Sometimes you <That is as in "you, plural?"> say Iwaki are better )except the 400 series), <Sometimes this line is> other times Eheim, other times a reference to a German pump, (assuming GRI??) <Don't know what this acronym refers to>   I have a 150 gallon tank with an overflow and a glass refugium for this tank. Everyone seems to say you prefer Eheim pumps. Would this be a good pump for a shark tank? <Yes> I am wanting to rule out the MagDrive for now in case your theory of the magnetic and electrical pumps are the source of my sharks pink bellies. <Stray current, dipole moment does adversely effect Elasmobranch fishes...> (Right now they have a submerged Mag 9.5 running their tank). If so would the Eheim 1260 or 1262 be best for this 150 tank with about 4' head? <The bigger the better> I was thinking on putting a SCWD and spitting the water so it would rotate from one end of the tank to the other. <I would not use such a device here... Better for shark species in small volumes (tens of thousands of gallons or less) to have continuous "high" water movement that is unidirectional... to "swim against", provide for "ram jet ventilation" in addition to their buccal suction efforts at respiration... Is this understood?> Would this affect the backpressure of the pump? <Yes... drops off to zip during the changes in direction> My overall concern is for the sharks longevity and to have a quiet quality pump. <Understood, and agreed>      The current and new tank both have sand as substrate. <Smooth sand... carbonaceous in composition... Not siliceous>      Thank you in advance   -Michael <Keep reading. Bob Fenner>

Electro magnetic air pump/ Sharks   8/31/06 Hi Bob, <Joe> Was hoping you could shed some light on the myth that sharks are sensitive to electro magnetic fields? <Mmm, not a myth. Established fact> I am thinking of purchasing a new air pump for my tank, although it is described as operating via an electro-magnetic motor. I have a port Jackson shark in my tank, and was wondering if this would affect him, or any shark in general. <Not likely... through the air... or even if this pump is placed near the tank> Also, could you please tell me what a sufficient air output in an 8ft tank should be (if there is a suggested air volume at all)? The air pump I have selected distributes 70 litres per minute. <... At what pressure? Depends on the depth, number of discharges... what mechanical diffuser devices, other outputs are employed. 70 LPM is a bunch of volume> Thanks Joe. <Bob Fenner>

Leopard shark - Metal, Stray Voltage Concerns One more question I neglected to ask, concerning metal and stray voltage in my tank. I removed my powerheads from my tank and I am now using bulkheads to feed current to the tank. This is coming from a Via Aqua 3600 powerhead in my sump (and I wanted to add at least one more). <... stray current will/does easily pass (get conducted if you want) in seawater via continuous water contact...> I've read however you should not even use powerheads in the sump. <Correct!> How can I provide adequate circulation otherwise. Are there any powerheads you can recommend that contain little or no metal that would disrupt my shark? Thanks in advance <... There are direct and coated magnetic drive mechanisms for external/emersed pumps... Bob Fenner> 

Coral Catshark Hello,  I hope this email finds you well. As always I have to thank you for the energy you expend helping us would be marine aquarists. Not that I expect you to remember but I emailed a few months ago regarding potential shark species for my tank. You advised me that coral Catshark (Atelomycterus marmoratus) or marble Catshark (Atelomycterus macleayi) would be best suited to my tank. Well after waiting for several months, keeping my tank minimally stocked, I finally got one. He is almost two feet. Only problem is I'm not certain if it is a coral or marble Catshark. Photos of the two closely related species aren't easy to come by and they seem to depict the same shark. Could you supply me with some distinguishing features between the two? <Please take a look at www.fishbase.org or your copy of Scott Michaels' "Sharks & Rays".> Also just to verify, I'll run my tank parameters by you to be certain everything is in order. 180 gallon (6' long, almost 3' wide), 50 gallon sump, trickle filter, 40 pounds of LR, sand bed, Aquamedic skimmer rated for 250 gal, two 802 powerheads. Is this enough aeration?  <You neglected to mention your return pump and its rating. A test for dissolved oxygen would confirm either way.> Temp: 79, pH: 8.3, Ammonia: 0, Nitrite: O Fish: 4" black volitans, 2" fuzzy dwarf lion, 4" Naso tang, 3" tomato clown and couple of damsels. Tank has been running for 7 months. Compatibility? <To me, if you are going to have a shark tank, have a shark tank. I would have left everyone else out. I do not see any out and out compatibility problems, but this tank seems overstocked or will be when everyone reaches full size.> I've done my research and believe I've provided a good home for this creature. Nonetheless, your expert advise is of great value and duly appreciated.  <Have a nice day! -Steven Pro>

Re: Coral Catshark I had checked Scott Michael's book. He lists tank size for a coral cat shark at 75 gallons. <That is the second time someone has said that. I am going to have to get a copy for myself. I cannot imagine he means as a final, healthy home. To me, a 180 is a good starter, but not the last tank you will need for an animal this size. They grow to three feet. The tank needs to be at least that wide, so they can turn around as adults, and three to four times that long, so they can swim a bit.>
<<Mmm, have checked... and this gallonage is only stated for small species of Catsharks. RMF>> Given that figure, I assumed perhaps incorrectly that my 180 gallon tank would be able to sustain other fishes besides the shark.  <Yes, an incorrect assumption IMO.> Your point is well taken though that the fish in my tank, particularly the Naso and Volitans will eventually put too much strain on the system. However, so long as my tank parameters remain healthy, I am not certain why the tank needs to be species specific. If you don't mind, could you please elaborate on your reasons for a species specific tank.  <Mainly because this is an incredibly large fish that is going to leave behind large waste and tax the system heavily. You do not need the additional waste from other fish. Plus, my recommendation generally separates the people that really, really want a shark from the casual shark hobbyist. If someone is not willing to have a species specific display, they are usually not going to save the tens of thousands of dollars to set up a tank large enough to house a shark permanently.> I also have two more questions. The flow rate on my pump is 850 gph coupled with the two 802 powerheads and the trickle filter is this enough aeration and circulation? <It seems like rather modest circulation to me. That 850 gph is a zero head pressure. I would ballpark it at no more than 500 gph actual plus the two 802's are rated at 400 gph (clean). Realistically, I would bet you have no more than 1200 gph total circulation.> I'm trying to track down an oxygen test kit but haven't been able to find one. <This should be fairly easy to find one on the internet.> Also my lighting consists of 110 watt, 48" power compacts, is this too bright?  <No> Thanks for your expertise. I hope the questions of a novice don't put too much strain your patience.  <That is who we primarily help everyday, new hobbyists. Have a nice day! -Steven Pro>

More shark questions  Ran across your FAQs on the WetWebMedia site and am highly impressed and profoundly grateful. It¹s hard to get unbiased information regarding elasmobranchs (btw, if you¹re friends with the publisher of Aquarium Sharks & Rays, please smack those people for me and tell them to get busy!).  <I am... indeed... and have... on repeated occasions... I was their/our industry rep... very slow to get works in print, the markets... painful for them/us, the industry, writers,  photographers... the "end-users".> Couple of questions from reading your shark article. You mention that vitamin supplementation is highly recommended. I feed my shark a basic diet of shrimp and squid and supplement with frozen cubes (shark cubes, Spirulina algae, herbivore, etc.) for variety and to get some green stuff¹ into his diet. He greedily eats whatever I provide, so can you recommend specific vitamin supplements to ensure he¹s getting the nutrition he needs? <I would soak these foods with a liquid prep. like Selcon, Zoecon, Microvit, ahead of offering... if the animal/s are small (under three feet in length) and "sneak in" tablet types in their larger food items if they are more than 3 feet in length> Regarding electromagnetic fields, I don¹t have any pumps in the water itself, but I do have several HEFTY pumps underneath the tank (enclosed in a wooden tank stand), which circulate water through canister filters and return water from the sump. For that matter, what about chillers, they have pretty big motors? <Can be problematical depending on the vicinity of ferrous metals... but likely not a problem if you haven't experienced difficulties to date> I also have oscillating water returns (www.sea-swirl.com) that are electrically powered. The units themselves are mounted on top of the tank on the acrylic cross members, but the outlet tubes are in the water, just below water level. Should I fear any interference problems with my guy¹s ampullae of Lorenzini? <Likely not much as stated above... the motors to the last are embedded in epoxy> Lastly, in addition to moderating the shark¹s food intake (I feed to satiation once every 3 days), I regulate his metabolism by keeping the water cool (72-73 degrees) for a tropical shark. Is the concept of regulating metabolism by temperature valid, or is that just another Å'fish story¹ I picked up in my readings somewhere?  <This is valid, useful> I will say that just by observation, he seemed to be hungrier on feeding days when my chiller was down for maintenance. <Yes... in Biology, the Q-10 factor... doubling of metabolic rate with every increase of ten  degrees C...>> Thanks again for your wonderful advice and commitment to the hobby. J.D. Hill <A pleasure and honor my friend. Bob Fenner>

265 Gallon Setup Bob, I hope all is well with you. Wanted to get your advice on what types of filters, skimmer, U.V sterilizer to purchase for a 265 gallon tank I will be setting up shortly. <These are all posted on our site: www.WetWebMedia.com> I know I'll need a wet dry. <Hmm, no.> I want to get one large enough to house the heater. Would a few whisper 5 hang on the back of the tank filters and some powerheads for water movement suffice?  <No> It will be a fish only tank with a bamboo shark, ward's Wobbie, and a few compatible fish. I figure I will want to get the best possible skimmer because I am looking to do the least amount of water changes as possible( the price of sea salt adds up). Also, are there any large angels or triggers that wouldn't bother the sharks if they were smaller than the sharks and placed in the tank last? Thanks for your help. <Yes> PS. I did inquire about the Ward's Wobbegong at the Marine Center and they will alert me when they get them in. <All sounds good... now hit the WWM site... Bob Fenner>

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